The experimental study of Bauschinger effect in Mn18Cr18N austenitic stainless steel was presented by compression-tensile cyclic loading tests with the prestrains ranging from 0.005 to 0.1,which was illustrated utiliz...The experimental study of Bauschinger effect in Mn18Cr18N austenitic stainless steel was presented by compression-tensile cyclic loading tests with the prestrains ranging from 0.005 to 0.1,which was illustrated utilizing stress-strain curves and analysed by TEM images from aspects of microstructural mechanisms.Moreover,the Bauschinger effect and its associated roundness phenomenon in reverse flow curve with respect to different cycles and cyclic strain amplitudes were evaluated in a quantitative manner.The experimental results indicate that Bauschinger effect is apparent during the test.At smaller cyclic strain amplitude,intergranular backstress is the main source of Bauschinger effect.With further increasing of cycles,dislocation density increases and dislocation movement is hindered in the reverse deformation.Therefore,Bauschinger effect is weakened to some extent.At large cyclic strain amplitude,backstress originating from the dislocation pile-up at grain boundaries and the continuous formation of deformation twins dominate the Bauschinger effect.In addition,the backstress results in the roundness of reverse curve during cyclic loading.The larger value ofΔεp*,the more obvious the roundness of the reverse curve,and the more significant the Bauschinger effect.展开更多
A void growth model considering the Bauschinger effect(BE)is proposed for ductile materials sustaining impact loading.Numerical simulations of two high-velocity impact problems are carried out by our newly developed E...A void growth model considering the Bauschinger effect(BE)is proposed for ductile materials sustaining impact loading.Numerical simulations of two high-velocity impact problems are carried out by our newly developed Eulerian programs.The proposed model is tested by a plate impact problem and a qualitative agreement with the experiment is obtained.Then a more complicated problem,a plate impacted by a spherical projectile at a velocity of 6.0 km/s,is simulated.The numerical results are in better accordance with the experimental data when the BE is considered.The proposed model reveals that the BE has an obvious effect on the spall process.展开更多
Initial flow stress in tension and tension plus compression and coercivity after those processes in dual-phase steels have been measured. It was found that the values of coercivity for tension plus compression are sma...Initial flow stress in tension and tension plus compression and coercivity after those processes in dual-phase steels have been measured. It was found that the values of coercivity for tension plus compression are smaller than for pure tension, a phenomenon much like the Bauschinger effect in steels.展开更多
The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features.In this work,laminate dual-phase(DP)steels with high martensite content(laminate HMDP steels)were ...The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features.In this work,laminate dual-phase(DP)steels with high martensite content(laminate HMDP steels)were produced by a combination of warm rolling and intercritical annealing.Influence of rolling strain and annealing temperature on the microstructural evolution and mechanical properties of laminate HMDP steels were systematically studied.The strength of HMDP steels was significantly improved to~1.6 GPa associated with a high uniform elongation of 7%,as long as the laminate structure is maintained.The strengthening and ductilizing mechanisms of laminate HMDP steels are discussed based on the influence of laminate structure and the high martensite content,which promote the development of internal stresses and can be correlated to the Bauschinger effect as measured by the cyclic loadingunloading-reloading experiments.Detailed transmission electron microscopy(TEM)observation was applied to characterize the dislocation structure in the deformed ferrite.展开更多
The mechanical properties of metallic thin films deposited on a substrate play a crucial role in the performance of micro/nano-electromechanical systems(MEMS/NEMS)and flexible electronics. This article reviews ongoing...The mechanical properties of metallic thin films deposited on a substrate play a crucial role in the performance of micro/nano-electromechanical systems(MEMS/NEMS)and flexible electronics. This article reviews ongoing study on the mechanics of substrate-supported thin films, with emphasis on the experimental characterization techniques,such as the rule of mixture and X-ray tensile testing. In particular, the determination of interfacial adhesion energy, film deformation, elastic properties and Bauschinger effect are discussed.展开更多
基金the National Natural Science Foundation of China(No.51575372)the Science and Technology Research Plan(Industrial)Project of Shanxi Province,China(No.201603D121006-2)+1 种基金the Start-up Fund for Scientific Research of Taiyuan University of Science and Technology(No.20172011)the Fund for Shanxi Key Subjects Construction。
文摘The experimental study of Bauschinger effect in Mn18Cr18N austenitic stainless steel was presented by compression-tensile cyclic loading tests with the prestrains ranging from 0.005 to 0.1,which was illustrated utilizing stress-strain curves and analysed by TEM images from aspects of microstructural mechanisms.Moreover,the Bauschinger effect and its associated roundness phenomenon in reverse flow curve with respect to different cycles and cyclic strain amplitudes were evaluated in a quantitative manner.The experimental results indicate that Bauschinger effect is apparent during the test.At smaller cyclic strain amplitude,intergranular backstress is the main source of Bauschinger effect.With further increasing of cycles,dislocation density increases and dislocation movement is hindered in the reverse deformation.Therefore,Bauschinger effect is weakened to some extent.At large cyclic strain amplitude,backstress originating from the dislocation pile-up at grain boundaries and the continuous formation of deformation twins dominate the Bauschinger effect.In addition,the backstress results in the roundness of reverse curve during cyclic loading.The larger value ofΔεp*,the more obvious the roundness of the reverse curve,and the more significant the Bauschinger effect.
基金by the National Natural Science Foundation of China under Grant Nos 10732010,10972010 and 11028206.
文摘A void growth model considering the Bauschinger effect(BE)is proposed for ductile materials sustaining impact loading.Numerical simulations of two high-velocity impact problems are carried out by our newly developed Eulerian programs.The proposed model is tested by a plate impact problem and a qualitative agreement with the experiment is obtained.Then a more complicated problem,a plate impacted by a spherical projectile at a velocity of 6.0 km/s,is simulated.The numerical results are in better accordance with the experimental data when the BE is considered.The proposed model reveals that the BE has an obvious effect on the spall process.
文摘Initial flow stress in tension and tension plus compression and coercivity after those processes in dual-phase steels have been measured. It was found that the values of coercivity for tension plus compression are smaller than for pure tension, a phenomenon much like the Bauschinger effect in steels.
基金supported financially by the National Key R&D Program of China(No.2017YFA0204403)the National Natural Science Foundation of China(Nos.51931003,51601094,51601003,51701097 and 51901103)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.30917011106 and 30918011342)the Natural Science Foundation of Jiangsu Province(Nos.BK20170843and BK20180492)。
文摘The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features.In this work,laminate dual-phase(DP)steels with high martensite content(laminate HMDP steels)were produced by a combination of warm rolling and intercritical annealing.Influence of rolling strain and annealing temperature on the microstructural evolution and mechanical properties of laminate HMDP steels were systematically studied.The strength of HMDP steels was significantly improved to~1.6 GPa associated with a high uniform elongation of 7%,as long as the laminate structure is maintained.The strengthening and ductilizing mechanisms of laminate HMDP steels are discussed based on the influence of laminate structure and the high martensite content,which promote the development of internal stresses and can be correlated to the Bauschinger effect as measured by the cyclic loadingunloading-reloading experiments.Detailed transmission electron microscopy(TEM)observation was applied to characterize the dislocation structure in the deformed ferrite.
基金supported by the National Natural Science Foundation of China (Grants 11472186 and 11602083)the Natural Science Foundation of Hunan Province, China (Grant 2016JJ6044)
文摘The mechanical properties of metallic thin films deposited on a substrate play a crucial role in the performance of micro/nano-electromechanical systems(MEMS/NEMS)and flexible electronics. This article reviews ongoing study on the mechanics of substrate-supported thin films, with emphasis on the experimental characterization techniques,such as the rule of mixture and X-ray tensile testing. In particular, the determination of interfacial adhesion energy, film deformation, elastic properties and Bauschinger effect are discussed.
