Al-Mg alloys are considered to have potentials to form twins during deformation because Mg can reduce the intrinsicstacking fault energy?ISFE of Al.Nevertheless,twinning has rarely been found in Al-Mg alloys even subj...Al-Mg alloys are considered to have potentials to form twins during deformation because Mg can reduce the intrinsicstacking fault energy?ISFE of Al.Nevertheless,twinning has rarely been found in Al-Mg alloys even subjected to various severeplastic deformation(SPD)techniques.In order to probe the twinning propensity of Al-Mg alloys,first-principles calculations werecarried out to investigate the effects of Mg and vacancies on the generalized planar fault energy(GPFE)of Al.It is found that bothMg and vacancies exhibit a Suzuki segregation feature to the stacking fault,and have the influence of decreasing the?ISFE of Al.However,?ISFE does not decrease and the twinnability parameterτa of Al does not increase monotonically with increasing Mgconcentration in the alloy.On the basis ofτa evaluated from the calculated GPFE of Al-Mg alloys,we conclude that deformationtwinning is difficult for Al-Mg alloys even with a high content of Mg.Besides,the decrease of?ISFE caused by the introduction ofMg and vacancies is supposed to have the effect of improving the work-hardening rate and facilitating the formation of bandstructures in Al-Mg alloys subjected to SPD.展开更多
基金Project(222173) supported by the FRINATEK project ‘BENTMAT’ from the Research Council of Norway
文摘Al-Mg alloys are considered to have potentials to form twins during deformation because Mg can reduce the intrinsicstacking fault energy?ISFE of Al.Nevertheless,twinning has rarely been found in Al-Mg alloys even subjected to various severeplastic deformation(SPD)techniques.In order to probe the twinning propensity of Al-Mg alloys,first-principles calculations werecarried out to investigate the effects of Mg and vacancies on the generalized planar fault energy(GPFE)of Al.It is found that bothMg and vacancies exhibit a Suzuki segregation feature to the stacking fault,and have the influence of decreasing the?ISFE of Al.However,?ISFE does not decrease and the twinnability parameterτa of Al does not increase monotonically with increasing Mgconcentration in the alloy.On the basis ofτa evaluated from the calculated GPFE of Al-Mg alloys,we conclude that deformationtwinning is difficult for Al-Mg alloys even with a high content of Mg.Besides,the decrease of?ISFE caused by the introduction ofMg and vacancies is supposed to have the effect of improving the work-hardening rate and facilitating the formation of bandstructures in Al-Mg alloys subjected to SPD.
