Dependence of the morphology of α(Al)-Mg2Si eutectic on the solidification velocity, and its orientation characteristics were investigated by thermoanalysis, directional solidification and electron diffraction techni...Dependence of the morphology of α(Al)-Mg2Si eutectic on the solidification velocity, and its orientation characteristics were investigated by thermoanalysis, directional solidification and electron diffraction techniques in this study.The eutectic morphology transformed from lamellae to rods with the increasing of the solidification velocity. Simultaneously, the orientation relationship changed from (100)Mg2Si/(100)Al;[110]Mg2si/[110]al to (011)Mg2si/(121)Al;[111]Mg2Si/[111]Al and (010)Mg2Si/(110)Al; [100]Mg2Si/[111]Al. Transformation of the eutectic morphology was related to the change of the preferred orientation of phase Mg2si.展开更多
The deformation mechanisms and the flow stress behavior of a medium-manganese high-carbon steel during cold deformation at a strain rate of 10×5 s^-1 were explored using a universal testing machine,an X-ray diffr...The deformation mechanisms and the flow stress behavior of a medium-manganese high-carbon steel during cold deformation at a strain rate of 10×5 s^-1 were explored using a universal testing machine,an X-ray diffractometer,a field emission scanning electron microscope and a high-resolution transmission electron microscope.The results show that continuous step-up serrated flow behavior appears after the yielding point,and the true stress-strain curve is roughly divided into five stages based on distinctive densities and amplitudes of serration.The strengthening mechanisms of the experimental steel involve Cottrell atmosphere,twinning-induced plasticity(TWIP)efect and transformation-induced plasticity(TRIP)effect.TWIP effect is the dominant deformation mechanism,and deformation twins formed by TWIP effect comprise primary,secondary and nanotwins.Furthermore,TRIP effect arises in the local high-strain region.Carbon element plays a key role in the transformation of the deformation mechanism.A small amount of carbide precipitates around twin boundaries lead to the formation of local carbon-poor regions,and Md temperature and stacking fault energy of medium-manganese high-carbon steel are propitious to the occurrence of TRIP effect.In addition,the contributions of various deformation mechanisms to plasticity are calculated,and that of TWIP effect is the greatest.展开更多
文摘Dependence of the morphology of α(Al)-Mg2Si eutectic on the solidification velocity, and its orientation characteristics were investigated by thermoanalysis, directional solidification and electron diffraction techniques in this study.The eutectic morphology transformed from lamellae to rods with the increasing of the solidification velocity. Simultaneously, the orientation relationship changed from (100)Mg2Si/(100)Al;[110]Mg2si/[110]al to (011)Mg2si/(121)Al;[111]Mg2Si/[111]Al and (010)Mg2Si/(110)Al; [100]Mg2Si/[111]Al. Transformation of the eutectic morphology was related to the change of the preferred orientation of phase Mg2si.
基金The authors gratefully appreciate the financial support by the National Natural Science Foundation of China(Grant Nos.U1860201 and U1960115)the Basic Research Program of Key Laboratory of Liaoning Province(LZ2015035).
文摘The deformation mechanisms and the flow stress behavior of a medium-manganese high-carbon steel during cold deformation at a strain rate of 10×5 s^-1 were explored using a universal testing machine,an X-ray diffractometer,a field emission scanning electron microscope and a high-resolution transmission electron microscope.The results show that continuous step-up serrated flow behavior appears after the yielding point,and the true stress-strain curve is roughly divided into five stages based on distinctive densities and amplitudes of serration.The strengthening mechanisms of the experimental steel involve Cottrell atmosphere,twinning-induced plasticity(TWIP)efect and transformation-induced plasticity(TRIP)effect.TWIP effect is the dominant deformation mechanism,and deformation twins formed by TWIP effect comprise primary,secondary and nanotwins.Furthermore,TRIP effect arises in the local high-strain region.Carbon element plays a key role in the transformation of the deformation mechanism.A small amount of carbide precipitates around twin boundaries lead to the formation of local carbon-poor regions,and Md temperature and stacking fault energy of medium-manganese high-carbon steel are propitious to the occurrence of TRIP effect.In addition,the contributions of various deformation mechanisms to plasticity are calculated,and that of TWIP effect is the greatest.
