The mechanical properties and microstructure evolution of cold-deformed CrMnN austenitic stainless steel annealed in a temperature ranging from 50 ℃ to 650 ℃ for 90 min and at 550 ℃ for different time were investig...The mechanical properties and microstructure evolution of cold-deformed CrMnN austenitic stainless steel annealed in a temperature ranging from 50 ℃ to 650 ℃ for 90 min and at 550 ℃ for different time were investigated by tensile test, micro hardness test, and Transmission Electron Microscope （TEM）. The steel was strengthened when it got annealed at temperatures ranging from 100 ℃ to 550 ℃, while it was softened when it got annealed at temperatures ranging from 550 ℃ to 650 ℃. Annealing temperature had stronger effect on mechanical properties than annealing time. TEM observations showed that nano-sized precipitates formed when the steel was annealed at 150 ℃ for 90 min, but the size and density of precipitates had no noticeable change with annealing temperature and time. Recrystallization occurred when the steel was annealed at temperatures above 550 ℃ for 90 min, and its scale increased with annealing temperature. Nano-sized annealing twins were observed. The mechanisms that controlled the mechanical behaviors of the steel were discussed.展开更多
Based on uniaxial tensile and plane strain deformation tests, the effects of strain states on the stability of RA （retained austenite） in medium Mn steels, which were subjected to IA （intercritical annealing） and ...Based on uniaxial tensile and plane strain deformation tests, the effects of strain states on the stability of RA （retained austenite） in medium Mn steels, which were subjected to IA （intercritical annealing） and Q＆P （quenching and partitioning） processing, were investigated. The volume fractions of RA before and after deformation were measured at different equivalent strains. The transformation behaviors of RA were also investigated. The stability of RA differed across two different transformation stages at the plane strain state： the stability was much lower in the first stage than in the second stage. For the uniaxial ten sion strain state, the stability of RA corresponded only to a single transformation stage. The main reason was that there were two types of transformations from RA in the medium Mn steel for the plane strain state. One type was that the martensite originated in the strain-induced stacking faults （SISF）. The other type was the strain-induced directly twin martensite at a certain equivalent strain. However, for the uniax- ial tension state, only the strain-induced twin martensite was observed. Dislocation lines and dislocation tangles were also observed in specimens deformed at different strain states. In addition, complex micro- structures of stacking faults and lath-like phases were observed within a grain at the plane strain state.展开更多
The impact abrasive wear behaviors of light-weight austenitic Fe-24Mn-7Al-1Csteel with increasing impact wear conditions were studied by comparing with the modified Hadfield（Mn13Cr2）steel.Wear tests were performed w...The impact abrasive wear behaviors of light-weight austenitic Fe-24Mn-7Al-1Csteel with increasing impact wear conditions were studied by comparing with the modified Hadfield（Mn13Cr2）steel.Wear tests were performed with the MLD-10 abrasive wear testing machine.Main parameters such as impact energy,impacting frequency and wear time were evaluated.To explore the abrasive wear behaviors under different impact energies,the parameters including mass loss,wear resistance and hardness were evaluated in detail.The microstructures of the steels were further analyzed using optical microscopy（OM）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）and X-ray diffraction（XRD）.Results showed that the light-weight austenitic Fe-24Mn-7Al-1Csteel had a better wear resistance than Mn13Cr2 steel under the impact energy tested.The wear resistance of light-weight austenitic Fe-24Mn-7Al-1Csteel was about 1.09-1.17 times as high as that of Mn13Cr2 steel under low and medium impact energy（0.5-2.0J）conditions,and 1.41 times under high impact energy（4.0J）condition.In Mn13Cr2 steel,the evolution of dislocation substructure with increasing impact energy showed typical stacking fault,interaction of twins and dislocations,as well as mechanical twins.The high work-hardening rate in Fe-24Mn-7Al-1Csteel was caused by Taylor lattice and high density of dislocation tangles.展开更多
基金Funded by of Liaoning Science and Technology Bureau(No.2007221007)
文摘The mechanical properties and microstructure evolution of cold-deformed CrMnN austenitic stainless steel annealed in a temperature ranging from 50 ℃ to 650 ℃ for 90 min and at 550 ℃ for different time were investigated by tensile test, micro hardness test, and Transmission Electron Microscope （TEM）. The steel was strengthened when it got annealed at temperatures ranging from 100 ℃ to 550 ℃, while it was softened when it got annealed at temperatures ranging from 550 ℃ to 650 ℃. Annealing temperature had stronger effect on mechanical properties than annealing time. TEM observations showed that nano-sized precipitates formed when the steel was annealed at 150 ℃ for 90 min, but the size and density of precipitates had no noticeable change with annealing temperature and time. Recrystallization occurred when the steel was annealed at temperatures above 550 ℃ for 90 min, and its scale increased with annealing temperature. Nano-sized annealing twins were observed. The mechanisms that controlled the mechanical behaviors of the steel were discussed.
基金financial support of the State Key Research and Development Program of China(Grant No.2017YFB0304404)
文摘Based on uniaxial tensile and plane strain deformation tests, the effects of strain states on the stability of RA （retained austenite） in medium Mn steels, which were subjected to IA （intercritical annealing） and Q＆P （quenching and partitioning） processing, were investigated. The volume fractions of RA before and after deformation were measured at different equivalent strains. The transformation behaviors of RA were also investigated. The stability of RA differed across two different transformation stages at the plane strain state： the stability was much lower in the first stage than in the second stage. For the uniaxial ten sion strain state, the stability of RA corresponded only to a single transformation stage. The main reason was that there were two types of transformations from RA in the medium Mn steel for the plane strain state. One type was that the martensite originated in the strain-induced stacking faults （SISF）. The other type was the strain-induced directly twin martensite at a certain equivalent strain. However, for the uniax- ial tension state, only the strain-induced twin martensite was observed. Dislocation lines and dislocation tangles were also observed in specimens deformed at different strain states. In addition, complex micro- structures of stacking faults and lath-like phases were observed within a grain at the plane strain state.
文摘The impact abrasive wear behaviors of light-weight austenitic Fe-24Mn-7Al-1Csteel with increasing impact wear conditions were studied by comparing with the modified Hadfield（Mn13Cr2）steel.Wear tests were performed with the MLD-10 abrasive wear testing machine.Main parameters such as impact energy,impacting frequency and wear time were evaluated.To explore the abrasive wear behaviors under different impact energies,the parameters including mass loss,wear resistance and hardness were evaluated in detail.The microstructures of the steels were further analyzed using optical microscopy（OM）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）and X-ray diffraction（XRD）.Results showed that the light-weight austenitic Fe-24Mn-7Al-1Csteel had a better wear resistance than Mn13Cr2 steel under the impact energy tested.The wear resistance of light-weight austenitic Fe-24Mn-7Al-1Csteel was about 1.09-1.17 times as high as that of Mn13Cr2 steel under low and medium impact energy（0.5-2.0J）conditions,and 1.41 times under high impact energy（4.0J）condition.In Mn13Cr2 steel,the evolution of dislocation substructure with increasing impact energy showed typical stacking fault,interaction of twins and dislocations,as well as mechanical twins.The high work-hardening rate in Fe-24Mn-7Al-1Csteel was caused by Taylor lattice and high density of dislocation tangles.
