Influence of heat treatment on tribological behaviors of novel wrought aluminum bronze

Influence of heat treatment on mechanical properties and tribological behaviors of Ti and B modified wrought aluminum bronze were studied. The results show that different strength and plasticity combination of the alloy after solution treatment can be obtained by adjusting the ageing temperature. When aged at 450?℃, the tensile strength σ b, yield strength σ 0.2 , elongation δ and hardness of the alloy are 1?050?MPa, 780?MPa, 4.5%, HB282, respectively. When aged at 650?℃, those of the alloy are 905?MPa, 600?MPa, 12%, HB232, respectively. Under boundary lubrication condition with pressure above 22.2?MPa, alloy with low temperature ageing has the best wear property. However, under the condition involving impact or shock loading, alloy with high temperature ageing is preferable. If the load is not heavy, the alloy under extrusion state is favorable for wear resisting parts.

Influence of Isothermal Treatment on Superelastic Behavior of Cu-13.8Al-4.0Ni(mass fraction) Single Crystals

The superelastic behaviors of different isothermal treated Cu-13.SAl-4.ONi (mass fraction) single crystals were studied by applying tensile stress along <001> of the d phase. The different isothermal specimens have different superelastic behavior due to the change of the ratio of stress-induced r1 and β1. The superelasticity of r1 phase tends to that of g; phase with cycling. Typical stabilization of stress-induced martensite above Ap results in residual deformation. Due to the reverse transformation of 7I, there is a deviation of pseudo-yield stress from linear relation with temperature at relatively low stress.

Mechanical properties, corrosion behaviors and microstructures of 7075 aluminium alloy with various aging treatments

The influence of two novel aging treatments, T6I6 (130 ℃, 80 min + 65 ℃, 240 h+130 ℃, 18 h) and high-temperature pre-precipitation(HTPP) aging (445 ℃, 30 min+120 ℃, 24 h) on the tensile properties, intergranular corrosion, exfoliation corrosion behaviors and microstructures of 7075 Al alloy was studied, which were compared with the T6, T73 and RRA treatments. Fine η′ precipitate with high density was obtained in the alloy with the T6 and RRA treatments. The η′ precipitate density in the HTPP aged alloy is decreased due to the formation of coarse particles during the pre-precipitation process at high temperature of 445 ℃. The 7075-T6I6 alloy possesses higher precipitate density and whole precipitate volume fraction within the grain than the 7075-T73 alloy, and its whole precipitate volume fraction is even greater than that of the 7075-T6 alloy. Compared with T6 treatment, the RRA, T73, T6I6 and HTPP aging treatments cause the discontinuous distribution of the η precipitates at the grain boundary, which decreases the intergranular corrosion and exfoliation corrosion susceptibility of the alloy. Meanwhile, the T6I6 and RRA treatments can keep the high strength of the 7075 Al alloy, but the studied HTPP aging and T73 treatments lower its strength.

Deformation Behavior and Formability of Gradient Nano-grained AISI 304 Stainless Steel Processed by Ultrasonic Impact Treatment

The deformation behavior and formability of gradient nano-grained（GNG） AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test（SPT）. The GNG top layer was fabricated on coarse grains（CG） AISI 304 by ultrasonic impact treatment. The results showed that the CG substrate could effectively suppress the strain localization of NC in GNG layer, and an approximate linear relationship existed between the thickness of substrate（h） and uniform true strain before necking（ε_（unif））. Grain growth of NC was observed at the stress state with high Stress triaxiality T, which led to better ductility of GNG/CG 304 in SPT, as well as similar true strain after the onset of necking（ε_（neck）） compared with coarse 304 in tensile test. Ei-values of GNG/CG 304 with different structures were nearly the same at different punch speeds, and good formability of GNG/CG 304 was demonstrated. However, punch speed and microstructure needed to be optimized to avoid much lost of membrane strain region in biaxial stress state.

Relationship between Heat Treatment and Corrosion Behavior of Mg-15Y Alloy

The corrosion behaviors of a basic type of RE-containing magnesium alloy Mg-15Y processed by different heat treatment methods were studied in 3.5% NaC1 solution at room temperature. The amount of Mg24Y5 phase decreased with the extending of homogenization treatment. The time for achieving dissolving equilibrium of homogenization treatment at 525, 535, and 545 ℃ was 24, 20, and 8 h, respectively. The corrosion behavior of Mg-15Y alloy was studied using immersion, hydrogen evolution and electrochemical tests. The experimental results revealed that the heat treatment improved the corrosion resistance, and the corrosion resistance became better with increasing the heat treatment time. The corrosion mode of the alloy after heat treatment was microgalvanic corrosion consisting of the cathodic Mg24Y5 phase and anodic α-Mg matrix, and Mg-15Y exhibited favorable uniform corrosion mode in NaC1 solution. The volume and increasing tendency of the homogenization treatment samples were both more than those of the as-cast sample.

Corrosion Behavior of Cu/Ni Coatings on Ti-6Al-4V Alloy after Diffused Treatment

To improve the low thermal conductivities and poor wear resistances of TC4(Ti-6Al-4V)alloy,the most widely used titanium alloy,the surface of TC4 alloys is modified by electroplating deposition of Ni and Cu layers,and then heat-treated to increase the diffusivity at the interface.In this paper,the corrosion behavior of Cu/Ni coatings on TC4 alloy at different heat treatment processes was investigated in 3.5 wt%Na Cl by the electrochemical analysis,and the microstructure and composition of corrosion products was carried out to reveal the corrosion resistance mechanism of Cu/Ni coatings.It was found that the corrosion resistance was significantly influenced by heat treatment temperature.With the increasing diffusion treatment temperature from 500 to 700℃,the corrosion potential positively shifted from-330.87 to-201.14 m V,and the corrosion current density decreased from 4.02×10^-3 to 0.514×10^-3 m A/cm^2.However,when heat treatment temperature increased to 800℃,the corrosion potential negatively shifted to-207.21 m V,and the current density increased to 1.62×10^-3 m A/cm^2.The diffusion behavior of Ti,Ni and Cu elements occurred and small amounts of Ni and Ti elements appeared on the specimen surface under different heat treatment temperature.Especially heattreated at 700℃,the smaller pore size,dense Cu2O film,and highly stable Ti O and Ni O oxide layer were formed,which dramatically enhanced the corrosion resistance of Cu/Ni coatings.Finally,a novel model of corrosion resistance was proposed based on the analysis mentioned above.

Knowledge of Health Communications Management and Treatment Seeking-Behavior Regarding Malaria in Uganda

In Uganda, there is still insufficient comprehension of malaria as a lethal disease especially in rural areas despite universal bed-net distribution coverage and effective anti-malarial treatment. Aim: To get evidence-based knowledge to establish the contribution of an individuals’ knowledge from various health communications that could increase their active involvement in health care especially seeking timely appropriate treatment for malaria or suspected malaria. Method: A cross-sectional survey using a correlational design was employed on a clustered sample of 380 rural households in 05 sub-counties of Kanungu district. Data were corrected between October 2016-January 2017 using researcher-administered questionnaires, key-informant interviews and focus group discussions. Correlation analysis was done. Result: There is a significant positive relationship between knowledge of health communications and treatment-seeking behavior (r = 0.312;p ≤ 0.01). Conclusion: Exposure to consistent Behavioral Change Communications messages influences treatment-seeking behaviour. Thus, in malaria-prone communities, it appears that other factors including sufficient targeted persuasive health communication are lacking in influencing personal orientations towards treatment-seeking behaviour. Therefore, proper Health Communications management supplements efforts from other disciplines and players, against malaria in Uganda.

Behavioral and Neural Enhancing Effects of a Summer Treatment Program in Children with Attention Deficit Hyperactivity Disorder

Deficiency in executive functioning is a core symptom of attention deficit hyperactivity disorder (ADHD). The brain part responsible for executive functions is the prefrontal cortex (PFC). Although drug-based interventions can improve PFC activity, reports on PFC activity being improved by behavioral treatment are lacking. We evaluated whether a summer treatment program (STP) administering comprehensive behavioral treatment would increase PFC activity in children with ADHD. We examined behavioral and neural changes in 20 children before and after the STP, conducted over a 2-week period. We asked the parents/guardians to complete the Swanson, Nolan, and Pelham IV scale to assess severity of ADHD. The main task evaluating executive control was the reverse Stroop task. To examine changes in physiological indices, we used near-infrared spectroscopy to measure changes in PFC activity. Subjective assessments by parents/guardians indicated that ADHD symptoms improved significantly. There was also significant improvement in the number of correct responses and interference rates in the reverse Stroop task. Furthermore, post-intervention PFC activity was significantly higher. These results suggest that the STP improved inhibitory control in executive function, which is considered as a key symptom of ADHD. The increase in PFC activity further suggests that the STP improves cognition through neural function.

Effectiveness of Family-Based Behavioral Treatment Based on Medication Behavior Barkley Compared with Drug Therapy in Reducing the Symptoms of Children with Attention Deficit Disorder-Hyperactivity

Children with attention deficit and hyper activity disorder have various problems such as low academic performance, social and communication problems, anxiety, depression, aggression, conduct disorder and delinquency, and also when they become adults, they have problems in social relationships that these problems can increase or decrease in dealing with family. Hence, this study was performed in order to examine the impact of family-based behavioral treatment compared with Barkley behavior therapy in reducing symptoms of children with attention deficit disorder—ADHD. To meet the aim, 20 of children with age range of 7 to 12 years old with attention deficit disorder—hyperactivity were selected in both experimental and control groups, and exposed to the treatment of behavioral family therapy groups and changes in behavior Barkley. Before and after the treatment, they were evaluated according to the scale of the Conner’s Parent Rating Scale-Revised Short Form (CPRS-R: S). Results of multivariate analysis of covariance indicated that there were significant differences between the experimental group who had received family-based behavioral treatments based on changes in behavior Barkley and a control group who had received drug treatment in variables, including conduct problems, learning problems, psychosomatic symptoms, and signs of impulsive hyperactivity, anxiety and hyperactivity (p < 0.01). These results could be guidance for counsel or sand therapists for children with attention deficit disorder—ADHD.

Effective of Behavioral Treatment Combined with Psychological Counseling for Female Coital Disorder of Chinese

Objective: To explore the effects of the behavioral treatment combined with psychological counseling on female coital disorder in China. Methods: One hundred and sixteen female patients with coital disorder were divided into sexual behavior training combined with psychological counseling group (group A, 59 cases) and psychological counseling alone group (group B, 57 cases). Results: Forty-five cases cured (76.27%), eight eases improved (13.56%), and six cases invalid (10.17%), the general rate of effectiveness being 89.83% in group A while eleven cases cured (19.30%), twenty-one cases improved (36.84%), and twenty-five cases invalid (43.86%), the general rate of effectiveness being 56.14% in group B. The curative effect of group A was better than group B (P Conclusions: The behavioral treatment combined with psychological counseling is significantly effective in treating female coital disorder than psychological counseling alone and its long term follow-up results show that most of patients were satisfied with their sex life. However, the response of behavioral treatment of some patients who had bad experience on sexual things in the progress of their growing up or had long course of disease were not so good which deserves our special attention in the future study.

Identifying Treatment and Healthcare Seeking Behavior as a Means of Early HIV/AIDS Intervention in Africa

Background: Late diagnosis of Human Immunodeficiency Virus (HIV) infection and delayed commencement of antiretroviral therapy (ART) in sub-Saharan Africa is known to contribute to high morbidity and mortality. It is therefore, prudent to develop innovative approaches to ensure early HIV diagnosis because patients with low immunity will usually develop opportunistic infections and seek some remedial action. A treatment and health care seeking behavior survey was carried out in semi-urban communities in Malaba and Busia in Kenya and Uganda to evaluate the treatment and healthcare seeking behavior among patients visiting randomly selected drugstores. Methodology: Random sampling was applied and questionnaires were used to collect information from 165 interviewees who visited drugstores seeking health information, treatment and other health related services. Results: The results indicated that among this group of people, 67% visited drugstores before any other health facility. 72.2% sought treatment for various illnesses and services ranging from headaches, body fever, gastro-intestinal disturbances, family planning pills, sexually transmitted infections and chronic medications. Among the patients interviewed, there were a number of factors that affected treatment choice. These included the distance to the facility as well as the absence of a consultation fee or fee for service. Conclusion: With proper support, drugstores can play a major role in the implementation of health interventions that seek to promote early diagnosis and treatment as well as play a pivotal role in educating the population on disease prevention and management. In Sub-Saharan Africa, drugstores can play a major role in HIV and AIDS interventions where most patients seek medical intervention for opportunistic infection.

Cognitive-Behavioral Group Treatment for Men Voluntarily Seeking Help for Violence towards Their Intimate Partners:The Impact of Treatment Components 4-7 Years after Therapy

Background: Even though domestic violence is a major problem, only a few studies have examined the long term sustainability of treatment for men who voluntarily seek help to stop their violent behavior towards intimate partners. Women are exposed to a much greater degree of serious violence and sexual abuse compared to men. Objective: The aim of this study was to identify which elements of the treatment program batterers found most useful four to seven years after program completion. Design: The participants consisted of a sample of men who had gone through anger management therapy four to seven years previously. Data on violence were collected through self-report before and four to seven years after treatment, using a modified version of the Conflict Tactics Scales. Results: The decrease in physical violence was statistically significant: t (36) = 8.43, p < 0.001 with a large effect size (eta squared = 0.66). Psychological violence also decreased significantly: t (36) = 9.21, p < 0.001 with a large effect size (eta squared = 0.7). The results indicate that the most important anger management techniques were extensively applied in former patients of the anger management treatment program. In total, about two out of three patients still used the techniques after ending treatment four to seven years earlier.

Evaluation of Diabetic Rats Behavior after Treatment by <i>Artemisia herba-alba</i>Relative to Insulin

The aim of the study was to evaluate the behavioral signs of diabetic rats after treatment by Artemisia herba-alba (AHA) and insulin. Method: Based on the induction of diabetes in wistar rats by intraperitoneal (I/P) injection of 60 mg/kg streptozotocin (STZ), then treated by AHA as 20 mg (I/P) and insulin subcutaneously (S/C). The samples of rats were: 1) Diabetic control, 2) Injected with insulin, 3) Injected with AHA, 4) Non diabetic rats, which were fostered for 21 day;then weighted and the behavioral tests were conducted. Results: The board hole tests (BHT) showed that: the induced diabetes reduced the cognition of the rats in view of Latency of the First Head Dipping (LFHD) in seconds, number of head dipping (NHD) and duration of head dipping (DHD) by 49.3%, while it’s improved in AHA and insulin treated rats by 52% and 69% in average respectively. The exploratory activity reduced in diabetic rats by 36%, while AHA and Insulin treated rats increased by 53% and 72% respectively. The rearing test showed an increase of anxiety among diabetic in form of duration of rearing, number of rearing and time spend in center by 51.7% in average respectively, while the anxiety reduced after treatment by AHA and insulin by 39% and 47.3% in average respectively. Also the diabetes increased the depression state by 106%, while the treatment by AHA and insulin reduced the depression state by 77% and 88% respectively. And VPT showed that: motor impairment occurred in diabetic cases and improved after AHA and insulin treatment.

Polymorphic Behavior of Syndiotactic Polypropylene Induced by Heat Treatment

The polymorphic behavior of syndiotactic polypropylene (s-PP) crystallized from the melt under different conditions was investigated by means of WAXD and DSC. The isothermal melt crystallization of s-PP proceeded in form I at tc≥ 110℃ and in form Ⅱ at tc≤110 ℃ s-PP crystallized nonisothermally from the melt was the mixture of forms and . With increasing the cooling rate (a), the content of form increased, and the content of form decreased. On heating, at 10 K/min, of quenched s-PP, it crystallized in form at t≤70 , continuing heating resulted in form form transition, which was an endothermal process.

不同预时效挤压态Mg−Gd−Y−Zn−Zr合金的再结晶行为和强化机制

通过控制预时效时间制备3种不同状态的试样,研究不同预时效状态对挤压态Mg−9.5Gd−4Y−2.2Zn−0.5Zr(质量分数,%)合金的动态再结晶行为(DRX)和性能的影响。结果表明,欠时效挤压(UAE)样品的细晶体积分数为17.4%,而峰时效挤压(PAE)和过时效挤压(OAE)样品的细晶体积分数分别达到89.7%和50.4%。在晶粒内部和晶界处分布的致密、细小的β颗粒相通过粒子激发形核机制显著提高了形核位点和位错密度。然而,致密针状γ'相抑制位错滑移,延迟DRX形核。PEA和OAE样品中细小晶粒的差异归因于原始颗粒相的数量和尺寸的不同,而其拉伸性能的差异归因于不同的显微组织。由于晶界强化和析出强化机制的贡献更大,PAE样品具有更优异的拉伸性能。

Effect of Thermal Cycling Treatment on Microyield Behavior of Al_2O_3p/Al Composite

An aluminum alloy (6061) matrix composite reinforced with 35% (vol.) Al 2O 3 particles was fabricated by squeeze casting method. The Al 2O 3 particles were spherical. The microyield behavior of the composite and the effect of different thermal cycling treatment on the microyield behaviors of the composite were studied. Based on TEM and HREM observation of microstructure, the mechanism of microyield behavior in the Al 2O 3p/6061 composite was analyzed. The results indicate that the microyield behavior of the Al 2O 3p/6061 composite can be described by Brown Lukens theory, which was used satisfactorily for aluminum alloys and other light alloys, and is affected greatly by the different thermal cycling treatment. The more the cycles of thermal cycling treatment, the higher to microyield strength at small strains. Thermal cycling treatment affects mainly the thermal mismatch stress and the density of movable dislocations in the matrix.

超高压力场下不同含量酒精对淀粉结构与理化性能的影响

本研究探讨了不同压力场(200、400、600 MPa)与不同含量酒精(30%~100%)作用下淀粉多尺度结构和理化性能的变化规律,旨为揭示超高压处理过程中溶液极性变化诱导淀粉多尺度结构转变进而调控其理化特性的分子机制。采用扫描电镜、小角X射线散射、X射线衍射、快速黏度分析等研究了不同压力场下溶液酒精含量对淀粉颗粒结构、层状结构、结晶结构以及糊化与老化特性的影响规律。结果发现,纯水相中的淀粉颗粒在600 MPa压力时,其颗粒态、层状及结晶结构破坏严重,淀粉糊峰值粘度次递下降;而在含有30%~100%酒精的溶液体系中,淀粉有序化结构向无序化形态的转变受到明显抑制,但其峰值粘度呈现无规律变化趋势。此外,超高压处理过程中溶液的酒精成分还可明显延缓淀粉糊的老化行为,且老化淀粉的结晶度与淀粉糊的回生值呈现较强正相关关系。综上,研究结果将为基于超高压与溶液极性处理定向调控淀粉结构与功能特性提供理论指导。

轧制态TiZrNbSn合金的再结晶行为

首先对冷轧态Ti-49Zr-21Nb-1.0Sn(TZNS1.0)合金分别在600、650、700、750、800和850℃进行再结晶退火处理10、20、30、60、90和120 min,随后采用光学显微镜(OM)和电子背散射衍射(EBSD)技术分析了热处理后合金的组织演变,计算了合金的再结晶激活能,建立了其再结晶动力学模型。结果表明:随着退火温度的升高,TZNS1.0合金的再结晶形核孕育时间缩短,β晶粒经历了回复、再结晶形核和长大阶段。随着退火时间的增加,合金的晶粒尺寸增大,但长大速度逐渐减小。TZNS1.0合金在750℃再结晶退火后,仅少数区域发生再结晶,大部分区域仍为变形组织,并存在许多小角度晶界、高密度位错和轧制织构。在800℃退火后,再结晶区域呈现大角度晶界,轧制织构和高密度位错被消除。退火温度进一步升高到850℃时,再结晶过程全部完成,合金晶粒明显长大。TZNS1.0合金的再结晶激活能为67.45 kJ/mol,850℃退火处理时,合金的再结晶动力学方程为x=1-e^(-0.05t 0.9)。

Improved Fatigue Behavior of Pipeline Steel Welded Joint by Surface Mechanical Attrition Treatment(SMAT)

A pipeline steel X80 with welded joint was subjected to surface mechanical attrition treatment （SMAT）. After SMAT, a nanostructure surface layer with an average grain size of about 10 nm was formed in the treated sample, and the fatigue limit of the welded joint was elevated by about 13% relative to the untreated joints. In the low and the high amplitude stress regimes, both fatigue strength and fatigue life were enhanced. Formation of the nanostructured surface layer played more important role in the enhanced fatigue behavior than that of residual stress induced by the SMAT.

组成对钠铝硅玻璃中钇锆酸盐纳米晶析晶性能的影响

基于含Y2O_(3)和ZrO_(2)的钠铝硅玻璃体系,研究了玻璃组分中Al_(2)O_(3)/Na2O摩尔比值(MAN)与SiO_(2)/Al_(2)O_(3)摩尔比值(MSA)对玻璃析晶性能的影响。研究结果表明,当MAN<1时,玻璃经热处理后表面析出钠霞石晶体;当MAN≥1时,玻璃热处理后析出钇锆酸盐纳米晶体,且此时微晶玻璃仍然具有不小于90%的高可见光透过率。对于固定MAN的玻璃,调整其MSA也能实现钇锆酸盐纳米晶的析出,且析出晶体尺寸随MSA增加而减小。随着热处理温度升高微晶玻璃样品中纳米晶体尺寸增大,维氏硬度也增大。