Herein,the evolution of long-period stacking ordered(LPSO)phases in the as-cast Mg-6Gd-1Zn-0.6Zr(wt.%)alloy are investigated via transmission electron microscopy(TEM)and atom probe tomography(APT).The TEM results reve...Herein,the evolution of long-period stacking ordered(LPSO)phases in the as-cast Mg-6Gd-1Zn-0.6Zr(wt.%)alloy are investigated via transmission electron microscopy(TEM)and atom probe tomography(APT).The TEM results reveal that two types of LPSO phase(a bulky interdendritic phase and a plate-like matrix LPSO phase)are formed in the as-cast sample.Most of the LPSO phases are confirmed to be of the 14H type,with a smaller proportion being of the 18R LPSO.Further,the APT results reveal that the composition of the interdendritic LPSO phase is closer to that of the ideal 14H phase compared to the matrix LPSO phase,and both the interdendritic and matrix LPSO phases exhibit a Gd/Zn ratio of 2.5,thereby indicating a deficient Zn content compared to the ideal 14H phase(i.e.,1.3).In addition,the influence of the LPSO phases on the deformation behavior is investigated at different compressive plastic strains using electron backscatter diffraction(EBSD)analysis to reveal twinning and slip behavior during deformation.The results indicate that the LPSO phase induces additional work hardening in the late stage of deformation via the suppression of{1011}compressive twinning and the activation of non-basal slip systems.展开更多
The Trait Activation Theory(TAT)is widely regarded as the most influential personality theory approach in psychology.The purpose of this study is to analyze the TAT’s role in the contemporary workplace.Which personal...The Trait Activation Theory(TAT)is widely regarded as the most influential personality theory approach in psychology.The purpose of this study is to analyze the TAT’s role in the contemporary workplace.Which personality traits are more likely to predict work success?Which characteristics should businesses prioritize throughout the recruiting and selection processes?According to the Trait Activation Theory,what is the significance of motivation in the workplace and how can employers find employees who can be more productive,efficient,and involved in the organization’s goals?A systematic review of past recent research was used to answer the questions raised above.Following the gathering and examination of multiple recent publications on the issue,it was determined that the use of this model had a favorable impact on individual and group performance,working relationships,manager job performance,and workplace creativity.展开更多
The Big Five Theory is considered as the most prominent personality theoretical approach in psychology.This paper aims to discuss the contribution of the Big Five Theory in the modern workplace.Which personality trait...The Big Five Theory is considered as the most prominent personality theoretical approach in psychology.This paper aims to discuss the contribution of the Big Five Theory in the modern workplace.Which personality traits are more predictive for job performance?Which traits should organizations take more in consideration during recruitment and selection processes?What is the meaning of motivation in the workplace and how employers could locate individuals who can be more productive,efficient,and engaged to the organization’s goals according to the Big Five personality model?The above questions are answered through the systematic review of previous contemporary studies.After the collection and review of several recent publications,regarding this subject,it was concluded that the application of this model positively affects employees’and group performance,working relationships,managers’work performance as well as innovation in workplace.展开更多
Work-team has emerged as an important unit composi ng the organization today. The concepts relating to the properties of team-role t hat fit with today’s business environment have attracted much attention from the th...Work-team has emerged as an important unit composi ng the organization today. The concepts relating to the properties of team-role t hat fit with today’s business environment have attracted much attention from the theorists and researchers. A team having a balanced composition of team-ro les is called a balanced team. Theoretically, a balanced team usually renders a better team performance. Therefore, to improve the performance of the team, mana gement needs to ensure that their work teams are composed of appropriate team me mbers with complementary skills, playing different roles, together forming a bal anced team. However, in certain situation, a balanced team can hardly be formed. For example , companies in Hong Kong are mostly the small-to-medium sized enterprises. The number of team-members is usually smaller than the required number for formula ting a balanced team. Also, as team members are required to travel often across borders, stable team can hardly be maintained. To resolve this problem, a different paradigm of team-role prevails here. Team -members autonomously supplant the roles of those missing members. We call this phenomenon the kinetic team role behavior. By using the methodology adopted from psychotherapy study, we propose a way to investigate this interesting and important characteristics of team-role.展开更多
This study investigated the relationships between human resource(HR)practices,employee psychological empowerment,employee innovative work behavior,and firm innovation capability in the context of the Information and C...This study investigated the relationships between human resource(HR)practices,employee psychological empowerment,employee innovative work behavior,and firm innovation capability in the context of the Information and Communication Technology(ICT)sector in Jordan.Employing the Social Exchange Theory(SET)as a guiding framework,this study explored how employee psychological empowerment and innovative work behavior mediated the influence of HR practices on a firm’s innovative capabilities.Drawing on extensive data collected from ICT organizations in Jordan,our analysis had several key findings.A significant positive correlation between HR practices and psychological empowerment was observed.Job design emerged as the most influential factor affecting psychological empowerment,whereas compensation had a weaker impact.Furthermore,we established that psychological empowerment significantly enhanced innovative work behavior,underscoring its role as a catalyst for innovative work behavior within the sector.Finally,our study supported the theory that psychological empowerment influenced a firms’innovation capabilities,emphasizing the pivotal role of employee empowerment in driving firm-level innovation in the Jordanian ICT sector.These findings provide insights for academic and practical audiences,clarifying how HR practices,employee psychological empowerment,and innovative work behavior collectively influenced firm innovation capability within the unique context of the Jordanian ICT sector.展开更多
Leader humility has emerged as an important topic in understanding the role of leadership in organizations in recent years.Though it was found to enhance subordinates’work performance and positive work behaviors,we a...Leader humility has emerged as an important topic in understanding the role of leadership in organizations in recent years.Though it was found to enhance subordinates’work performance and positive work behaviors,we are unaware of the psychological mechanism and boundary conditions underlying leader humility and employees’negative behaviors toward leaders.Drawing on social exchange theory and using a multistage sample including 273 employees and 55 supervisors in China,we demonstrated a negative indirect effect between leader humility and subordinates’counterproductive work behaviors toward supervisors(CWB-S)via interpersonal justice and trust in supervisor.Furthermore,we find that leader political skill moderates the effect of leader humility on interpersonal justice and trust in supervisor.The indirect effect of leader humility on subordinates’CWB-S through interpersonal justice is stronger when leader political skill is high,suggesting a moderated mediation model.Finally,we discuss the theoretical contributions and practical implications of this study,and highlight future directions for research on leader humility.展开更多
To examine the influence of grain boundary engineering(GBE)on the work hardening behavior,the tensile tests were carried out on the non-GBE and GBE AL6XN super-austenitic stainless steel(ASS)samples with a comparable ...To examine the influence of grain boundary engineering(GBE)on the work hardening behavior,the tensile tests were carried out on the non-GBE and GBE AL6XN super-austenitic stainless steel(ASS)samples with a comparable grain size at two strain rates of 10^(-2)s^(-1)and 10^(-4)s^(-1).The evolution of deformation microstructures was revealed by transmission electron microscopy(TEM)and quasi-in situ electron backscatter diffraction(EBSD)observations.The results show that the influence of GBE on the mechanical properties of AL6XN super-ASS is mainly manifested in the change of work hardening behavior.At the early stage of plastic deformation,GBE samples show a slightly lowered work hardening rate,since the special grain boundaries(SBs)of a high fraction induce a higher dislocation free path and a weaker back stress;however,with increasing plastic deformation amount,the work hardening rate of GBE samples gradually surpasses that of non-GBE samples due to the better capacity of maintainable work hardening that is profited from the inhibited dislocation annihilation by SBs.In a word,the enhanced capacity of sustained work hardening effectively postpones the appearance of necking point and thus efficaciously ameliorates the ductility of GBE samples under the premise of little changes in yield strength and ultimate tensile strength.展开更多
Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenchi...Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. Concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined.展开更多
The effect of particle deformation zone(PDZ) on the microstructure and mechanical properties of SiC_(p)/Mg-5Zn composites was studied.Meanwhile,the work hardening and so ftening behavior of SiC_(p)/Mg-5Zn composites i...The effect of particle deformation zone(PDZ) on the microstructure and mechanical properties of SiC_(p)/Mg-5Zn composites was studied.Meanwhile,the work hardening and so ftening behavior of SiC_(p)/Mg-5Zn composites influenced by PDZ size were analyzed and discussed using neutron diffraction under in-situ tensile deformation.The evolution of FWHM(full width at half maximum) extracted from the diffraction pattern of SiC_(p)/Mg-5Zn composites was used to interpret the modification of dislocation density during in-situ tension,which discovered the effect of dislocation on the work hardening behavior of SiC_(p)/Mg-5Zn composites.In addition,the tensile stress reduction(△P_i) values during in-situ tension test were calculated to analyze the effect of PDZ size on the softening behavior of SiC_(p)/Mg-5Zn composites.The results show that the work hardening rate of SiC_(p)/Mg-5Zn composites increased with the enlargement of PDZ size,which was attributed to the grain size of SiC_(p)/Mg-5Zn composites increased with the enlargement of PDZ size.Moreover,the stress reduction(△P_i) values increased continuously during in-situ tensile for SiC_(p)/Mg-5Zn composites due to the increased stored energy produced during plastic deformation,which provided a driving force for the softening effect.However,the effect of grain size on the softening behavior is greater than that of the stored energy,which led to the tensile stress reduction(△P_i) values of P30(d_(PDZ)=30 μm)-SiC_(p)/Mg-5Zn composite were higher than that of P60(d_(PDZ)=60 μm)-SiC_(p)/Mg-5Zn composite when the ε_(ri) were 0.25,0.5,0.75 and 1,respectively.展开更多
The constant strain rate uniaxial compression tests were conducted in this paper for studying the work hardening behavior and revealing the underlying microstructure evolution involved in the plastic response of the n...The constant strain rate uniaxial compression tests were conducted in this paper for studying the work hardening behavior and revealing the underlying microstructure evolution involved in the plastic response of the nickel-based Inconel X-750 alloy. The work hardening rate versus true strain plots of Inconel X-750 alloy resembled that of low-stacking-fault energy (SFE) alloys with distinct four stages. The dislocations were found in the planar arrangements at a strain of 0.1 located at the onset of stage II, and the dislocation density was increased and the planar arrangement configuration was partially destroyed at a strain of 0.36 located in stage III. It was unexpected that deformation twins were observed at a strain of 0.69 located in stage IV although the alloy has been classified into materials with a higher SFE value. The result is different with a similar study, in which the deformation twins were absent in Ni-Cr-based alloy Inconel 625 even when the strain was as high as 0.65. It was deemed that the low level of solution strengthening favored the deformation of matrix and the activation of slip system for twining in Inconel X-750 alloy. Unlike the low-SFE alloys that the twins were always formed at the end of stage Ⅰ, the higher SFE delayed the twin formation to stage IV for Inconel X-750 alloy. The well- developed planar dislocation configuration gave rise to the stage Ⅱ with a slightly decreasing rate, the collapse of planar dislocation arrangements caused the occurrence of stage Ⅲ with an accelerated decreasing rate, and the twin formation led to the stage IV with a nearly constant work hardening rate.展开更多
The effects of deforming temperatures on the tensile behaviors of quenching and partitioning treated steels were investigated. It was found that the ultimate tensile strength of the steel decreased with the increasing...The effects of deforming temperatures on the tensile behaviors of quenching and partitioning treated steels were investigated. It was found that the ultimate tensile strength of the steel decreased with the increasing temperature from 25 to 100 ℃, reached the maximum value at 300 ℃, and then declined by a significant extent when the temperature further reached 400 ℃. The total elongations at 100, 200 and 300 ℃are at about the same level. The steel achieved optimal mechanical properties at 300 ℃due to the proper transformation behavior of retained austenite since the stability of retained austenite is largely dependent on the deforming temperature. When tested at 100 and 200 ℃, the retained aus tenite was reluctant to transform, while at the other temperatures, about 10 vol. % of retained aus- tenite transformed during the tensile tests. The relationship between the stability of retained austenite and the work hardening behavior of quenching and partitioning treated steels at different deforming temperatures was also studied and discussed in detail. In order to obtain excellent mechanical properties, the stability of retained austenite should be carefully controlled so that the effect of transforma tion-induced plasticity could take place continuously during plastic deformation.展开更多
The microstructure and mechanical properties of NANOBAIN steel treated at different isothermal temperatures were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),uniaxial ten...The microstructure and mechanical properties of NANOBAIN steel treated at different isothermal temperatures were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),uniaxial tensile tests and X-ray diffraction(XRD).It was found that bainitic ferrite(BF)plate was made of basic shear transformation units arranged in the same direction of subunits.The existence of defects,such as nanoscale twinning and dislocation,suggested that the growth of transformation units was controlled by the surrounding defect plane with dislocation,which was consistent with the moving direction of BF/austenite interface parallel to the twinning plane.The behavior of work hardening indicated that mechanical stability of microstructures obtained at 250 ℃ and 300 ℃ was much more stable than that obtained at 210℃.The evolution of carbon partitioning in retained austenite and bainitic ferrite also indicated that austenite was enriched in carbon at the initial stage step by step;after the formation of BF,the austenite did not seem to be greatly enriched in carbon and the carbon content showed a little decrease instead;subsequently,aphenomenon of little decarburization of supersaturated bainitic ferrite has also been found.展开更多
Based on the view of transformational leadership theory, the relationship between transformational leadership and the counterproductive work behavior of knowledge employee was researched. 221 valid questionnaires were...Based on the view of transformational leadership theory, the relationship between transformational leadership and the counterproductive work behavior of knowledge employee was researched. 221 valid questionnaires were obtained through the survey. Hierarchical regression analysis results showed that the virtue was significantly negative related to all the six dimensions of knowledge employee counterproductive work behavior, the vision incentive was significantly negative related to five dimensions of the knowledge employee counterproductive behavior except conservative intellectual behavior, the charisma was significantly negative related to five dimensions of the knowledge employee counterproductive work behavior except passive obedience behavior, personalized care was significantly negative related to five dimensions of the knowledge employee counterproductive behavior except immoral behavior. In short, transformational leadership was negatively related to the knowledge employee counterproductive work behavior.展开更多
基金This work was supported by the National Research Foundation of Korea(Grant number:NRF-2019K1A3A1A18116059 and NRF-2023R1A2C200529811)Austrian Science Fund(FWF)(P 32378-N37)Federal Ministry of Austria Education,Science and Research(BMBWF)(KR 06/2020).
文摘Herein,the evolution of long-period stacking ordered(LPSO)phases in the as-cast Mg-6Gd-1Zn-0.6Zr(wt.%)alloy are investigated via transmission electron microscopy(TEM)and atom probe tomography(APT).The TEM results reveal that two types of LPSO phase(a bulky interdendritic phase and a plate-like matrix LPSO phase)are formed in the as-cast sample.Most of the LPSO phases are confirmed to be of the 14H type,with a smaller proportion being of the 18R LPSO.Further,the APT results reveal that the composition of the interdendritic LPSO phase is closer to that of the ideal 14H phase compared to the matrix LPSO phase,and both the interdendritic and matrix LPSO phases exhibit a Gd/Zn ratio of 2.5,thereby indicating a deficient Zn content compared to the ideal 14H phase(i.e.,1.3).In addition,the influence of the LPSO phases on the deformation behavior is investigated at different compressive plastic strains using electron backscatter diffraction(EBSD)analysis to reveal twinning and slip behavior during deformation.The results indicate that the LPSO phase induces additional work hardening in the late stage of deformation via the suppression of{1011}compressive twinning and the activation of non-basal slip systems.
文摘The Trait Activation Theory(TAT)is widely regarded as the most influential personality theory approach in psychology.The purpose of this study is to analyze the TAT’s role in the contemporary workplace.Which personality traits are more likely to predict work success?Which characteristics should businesses prioritize throughout the recruiting and selection processes?According to the Trait Activation Theory,what is the significance of motivation in the workplace and how can employers find employees who can be more productive,efficient,and involved in the organization’s goals?A systematic review of past recent research was used to answer the questions raised above.Following the gathering and examination of multiple recent publications on the issue,it was determined that the use of this model had a favorable impact on individual and group performance,working relationships,manager job performance,and workplace creativity.
文摘The Big Five Theory is considered as the most prominent personality theoretical approach in psychology.This paper aims to discuss the contribution of the Big Five Theory in the modern workplace.Which personality traits are more predictive for job performance?Which traits should organizations take more in consideration during recruitment and selection processes?What is the meaning of motivation in the workplace and how employers could locate individuals who can be more productive,efficient,and engaged to the organization’s goals according to the Big Five personality model?The above questions are answered through the systematic review of previous contemporary studies.After the collection and review of several recent publications,regarding this subject,it was concluded that the application of this model positively affects employees’and group performance,working relationships,managers’work performance as well as innovation in workplace.
文摘Work-team has emerged as an important unit composi ng the organization today. The concepts relating to the properties of team-role t hat fit with today’s business environment have attracted much attention from the theorists and researchers. A team having a balanced composition of team-ro les is called a balanced team. Theoretically, a balanced team usually renders a better team performance. Therefore, to improve the performance of the team, mana gement needs to ensure that their work teams are composed of appropriate team me mbers with complementary skills, playing different roles, together forming a bal anced team. However, in certain situation, a balanced team can hardly be formed. For example , companies in Hong Kong are mostly the small-to-medium sized enterprises. The number of team-members is usually smaller than the required number for formula ting a balanced team. Also, as team members are required to travel often across borders, stable team can hardly be maintained. To resolve this problem, a different paradigm of team-role prevails here. Team -members autonomously supplant the roles of those missing members. We call this phenomenon the kinetic team role behavior. By using the methodology adopted from psychotherapy study, we propose a way to investigate this interesting and important characteristics of team-role.
文摘This study investigated the relationships between human resource(HR)practices,employee psychological empowerment,employee innovative work behavior,and firm innovation capability in the context of the Information and Communication Technology(ICT)sector in Jordan.Employing the Social Exchange Theory(SET)as a guiding framework,this study explored how employee psychological empowerment and innovative work behavior mediated the influence of HR practices on a firm’s innovative capabilities.Drawing on extensive data collected from ICT organizations in Jordan,our analysis had several key findings.A significant positive correlation between HR practices and psychological empowerment was observed.Job design emerged as the most influential factor affecting psychological empowerment,whereas compensation had a weaker impact.Furthermore,we established that psychological empowerment significantly enhanced innovative work behavior,underscoring its role as a catalyst for innovative work behavior within the sector.Finally,our study supported the theory that psychological empowerment influenced a firms’innovation capabilities,emphasizing the pivotal role of employee empowerment in driving firm-level innovation in the Jordanian ICT sector.These findings provide insights for academic and practical audiences,clarifying how HR practices,employee psychological empowerment,and innovative work behavior collectively influenced firm innovation capability within the unique context of the Jordanian ICT sector.
基金National Natural Science Foundation of China(project code:7164001571772176)Yuyou Talent Program of NCUT,and the 2019 PhD Joint Training Scholarship of Renmin Business School.
文摘Leader humility has emerged as an important topic in understanding the role of leadership in organizations in recent years.Though it was found to enhance subordinates’work performance and positive work behaviors,we are unaware of the psychological mechanism and boundary conditions underlying leader humility and employees’negative behaviors toward leaders.Drawing on social exchange theory and using a multistage sample including 273 employees and 55 supervisors in China,we demonstrated a negative indirect effect between leader humility and subordinates’counterproductive work behaviors toward supervisors(CWB-S)via interpersonal justice and trust in supervisor.Furthermore,we find that leader political skill moderates the effect of leader humility on interpersonal justice and trust in supervisor.The indirect effect of leader humility on subordinates’CWB-S through interpersonal justice is stronger when leader political skill is high,suggesting a moderated mediation model.Finally,we discuss the theoretical contributions and practical implications of this study,and highlight future directions for research on leader humility.
基金financially supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.51871048 and 52171108。
文摘To examine the influence of grain boundary engineering(GBE)on the work hardening behavior,the tensile tests were carried out on the non-GBE and GBE AL6XN super-austenitic stainless steel(ASS)samples with a comparable grain size at two strain rates of 10^(-2)s^(-1)and 10^(-4)s^(-1).The evolution of deformation microstructures was revealed by transmission electron microscopy(TEM)and quasi-in situ electron backscatter diffraction(EBSD)observations.The results show that the influence of GBE on the mechanical properties of AL6XN super-ASS is mainly manifested in the change of work hardening behavior.At the early stage of plastic deformation,GBE samples show a slightly lowered work hardening rate,since the special grain boundaries(SBs)of a high fraction induce a higher dislocation free path and a weaker back stress;however,with increasing plastic deformation amount,the work hardening rate of GBE samples gradually surpasses that of non-GBE samples due to the better capacity of maintainable work hardening that is profited from the inhibited dislocation annihilation by SBs.In a word,the enhanced capacity of sustained work hardening effectively postpones the appearance of necking point and thus efficaciously ameliorates the ductility of GBE samples under the premise of little changes in yield strength and ultimate tensile strength.
基金supported by the National Natural Science Foundation of China(No.51401221,51622401 and 51628402)the support from the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB06050100)
文摘Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. Concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined.
基金supported financially by the National Natural Science Foundation of China(Nos.51771128 and 51771129)the Shanxi Province Science and Technology Major Projects(No.20181101008)the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi。
文摘The effect of particle deformation zone(PDZ) on the microstructure and mechanical properties of SiC_(p)/Mg-5Zn composites was studied.Meanwhile,the work hardening and so ftening behavior of SiC_(p)/Mg-5Zn composites influenced by PDZ size were analyzed and discussed using neutron diffraction under in-situ tensile deformation.The evolution of FWHM(full width at half maximum) extracted from the diffraction pattern of SiC_(p)/Mg-5Zn composites was used to interpret the modification of dislocation density during in-situ tension,which discovered the effect of dislocation on the work hardening behavior of SiC_(p)/Mg-5Zn composites.In addition,the tensile stress reduction(△P_i) values during in-situ tension test were calculated to analyze the effect of PDZ size on the softening behavior of SiC_(p)/Mg-5Zn composites.The results show that the work hardening rate of SiC_(p)/Mg-5Zn composites increased with the enlargement of PDZ size,which was attributed to the grain size of SiC_(p)/Mg-5Zn composites increased with the enlargement of PDZ size.Moreover,the stress reduction(△P_i) values increased continuously during in-situ tensile for SiC_(p)/Mg-5Zn composites due to the increased stored energy produced during plastic deformation,which provided a driving force for the softening effect.However,the effect of grain size on the softening behavior is greater than that of the stored energy,which led to the tensile stress reduction(△P_i) values of P30(d_(PDZ)=30 μm)-SiC_(p)/Mg-5Zn composite were higher than that of P60(d_(PDZ)=60 μm)-SiC_(p)/Mg-5Zn composite when the ε_(ri) were 0.25,0.5,0.75 and 1,respectively.
文摘The constant strain rate uniaxial compression tests were conducted in this paper for studying the work hardening behavior and revealing the underlying microstructure evolution involved in the plastic response of the nickel-based Inconel X-750 alloy. The work hardening rate versus true strain plots of Inconel X-750 alloy resembled that of low-stacking-fault energy (SFE) alloys with distinct four stages. The dislocations were found in the planar arrangements at a strain of 0.1 located at the onset of stage II, and the dislocation density was increased and the planar arrangement configuration was partially destroyed at a strain of 0.36 located in stage III. It was unexpected that deformation twins were observed at a strain of 0.69 located in stage IV although the alloy has been classified into materials with a higher SFE value. The result is different with a similar study, in which the deformation twins were absent in Ni-Cr-based alloy Inconel 625 even when the strain was as high as 0.65. It was deemed that the low level of solution strengthening favored the deformation of matrix and the activation of slip system for twining in Inconel X-750 alloy. Unlike the low-SFE alloys that the twins were always formed at the end of stage Ⅰ, the higher SFE delayed the twin formation to stage IV for Inconel X-750 alloy. The well- developed planar dislocation configuration gave rise to the stage Ⅱ with a slightly decreasing rate, the collapse of planar dislocation arrangements caused the occurrence of stage Ⅲ with an accelerated decreasing rate, and the twin formation led to the stage IV with a nearly constant work hardening rate.
基金financial support of the National Key Research and Development Program of China(No.2017YFB0304401)National Natural Science Foundation of China(Nos.U1564203,51571141 and 51201105)the support provided by Shanghai Key Laboratory of Materials Laser Processing and Modification,Shanghai Jiao Tong University
文摘The effects of deforming temperatures on the tensile behaviors of quenching and partitioning treated steels were investigated. It was found that the ultimate tensile strength of the steel decreased with the increasing temperature from 25 to 100 ℃, reached the maximum value at 300 ℃, and then declined by a significant extent when the temperature further reached 400 ℃. The total elongations at 100, 200 and 300 ℃are at about the same level. The steel achieved optimal mechanical properties at 300 ℃due to the proper transformation behavior of retained austenite since the stability of retained austenite is largely dependent on the deforming temperature. When tested at 100 and 200 ℃, the retained aus tenite was reluctant to transform, while at the other temperatures, about 10 vol. % of retained aus- tenite transformed during the tensile tests. The relationship between the stability of retained austenite and the work hardening behavior of quenching and partitioning treated steels at different deforming temperatures was also studied and discussed in detail. In order to obtain excellent mechanical properties, the stability of retained austenite should be carefully controlled so that the effect of transforma tion-induced plasticity could take place continuously during plastic deformation.
基金Item Sponsored by National Natural Science Foundation of China(51271035)
文摘The microstructure and mechanical properties of NANOBAIN steel treated at different isothermal temperatures were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),uniaxial tensile tests and X-ray diffraction(XRD).It was found that bainitic ferrite(BF)plate was made of basic shear transformation units arranged in the same direction of subunits.The existence of defects,such as nanoscale twinning and dislocation,suggested that the growth of transformation units was controlled by the surrounding defect plane with dislocation,which was consistent with the moving direction of BF/austenite interface parallel to the twinning plane.The behavior of work hardening indicated that mechanical stability of microstructures obtained at 250 ℃ and 300 ℃ was much more stable than that obtained at 210℃.The evolution of carbon partitioning in retained austenite and bainitic ferrite also indicated that austenite was enriched in carbon at the initial stage step by step;after the formation of BF,the austenite did not seem to be greatly enriched in carbon and the carbon content showed a little decrease instead;subsequently,aphenomenon of little decarburization of supersaturated bainitic ferrite has also been found.
文摘Based on the view of transformational leadership theory, the relationship between transformational leadership and the counterproductive work behavior of knowledge employee was researched. 221 valid questionnaires were obtained through the survey. Hierarchical regression analysis results showed that the virtue was significantly negative related to all the six dimensions of knowledge employee counterproductive work behavior, the vision incentive was significantly negative related to five dimensions of the knowledge employee counterproductive behavior except conservative intellectual behavior, the charisma was significantly negative related to five dimensions of the knowledge employee counterproductive work behavior except passive obedience behavior, personalized care was significantly negative related to five dimensions of the knowledge employee counterproductive behavior except immoral behavior. In short, transformational leadership was negatively related to the knowledge employee counterproductive work behavior.