高锰TWIP钢拉伸时织构演变和孪生弱化织构的作用

研究室温下锰的质量分数分别为26%和30%的两种晶粒较粗大的TWIP钢拉断过程中织构的演变规律及孪生弱化〈111〉织构的作用。结果表明,TWIP钢拉伸时形成较强的〈111〉织构,也形成由〈111〉取向晶粒的不同孪晶产生的接近〈100〉的弱织构,从而孪生弱化了〈111〉拉伸织构。粗的奥氏体晶粒促进孪生,从而加速〈111〉织构的弱化。拉伸过程中〈111〉取向的晶粒有利于形变孪生,〈100〉取向的晶粒不利于孪生。锰含量较低的26Mn钢出现少量的形变诱发ε-M,由于ε-M主要从〈111〉取向的形变孪晶内形成,因此也出现择优取向,形成倾转的基面织构,弱化了〈111〉织构。

Texture evolution and texture weakening by twinning in tensile-deformed high manganese TWIP steels

Texture evolution during tensile deformation and the weakening of 〈111〉 texture by twinning at room temperature were investigated in coarse-grained high manganese TWIP steels with 26% and 30% manganese,respectively.The results show that a dominant 〈111〉 texture develops during tensile deformation,and at the same time weak textures close to the 〈100〉 orientation are formed due to the twinning of 〈111〉 matrix grains,which weakens 〈111〉 texture.Coarse austenite grains facilitate twinning and thus accelerate 〈111〉 texture weakening.Besides,during tensile deformation austenite grains of 〈111〉 orientation are easy to twin,while grains of 〈100〉 orientation are difficult to twin.Small amount of ε-martensite is induced during tension in 26Mn steel of lower manganese content and it forms mainly within the twins in 〈111〉-oriented matrix.Therefore,it weakens 〈111〉 texture of matrix on the one hand and is also preferentially oriented producing a tilt basal microtexture on the other hand.