摘要
研究在单辊驱动轧制Al-5.6Zn-2.5Mg-1.4Cu合金过程中,材料显微组织和织构的变化,并详细研究其力学性能各向异性与显微组织和织构的关系。对样品固溶处理后立即进行单辊驱动轧制,厚度减薄率分别为10%、20%、40%和60%。通过光学和扫描电子显微镜对显微组织进行表征,通过X射线衍射仪对织构进行表征,并对拉伸力学性能进行分析。结果表明,减薄率为40%和60%的轧制样品,其面内各向异性值从固溶处理合金的11.6%分别显著降低到2.4%和3.1%。这是由于旋转立方织构的形成减小了总的织构强度以及动态再结晶过程中新晶粒的形成。由于样品中晶粒形貌和织构不同,样品轧制方向(RD)比横向(TD)的屈服强度高。沿RD存在的几个较强取向导致沿RD(0°)的Portevin–LeChatelier(PLC)效应明显低于沿HD(45°)和TD(90°)的。随着厚度减薄率的增大,织构强度减小,导致RD、HD和TD之间的应变硬化率差异减小。而对于减薄率为60%的样品,其RD、HD和TD的断裂面无差异,说明其断裂行为为各向同性。
The current research aimed to study the microstructure and texture development of the Al-5.6Zn-2.5Mg-1.4Cu alloy during single roll drive rolling process(SRDR).The relationship between mechanical property anisotropy and microstructure and texture was investigated in detail.The SRDR process was immediately performed on the solution-treated sample with four different thickness reductions of 10%,20%,40%,and 60%,respectively.Microstructural examination by optical and scanning electron microscopes,texture evaluation by X-ray diffraction,and mechanical properties evaluation by tensile tests were conducted.The results showed that the value of in-plane anisotropy was significantly reduced from 11.6%in solution-treated alloy to 2.4%and 3.1%in 40%and 60%reduction rolled samples,respectively.This was due to the formation of the Rotated Cube component,decreasing the overall texture intensity,and the formation of new grains through dynamic recrystallization.The yield strength in the rolling direction(RD)was higher than that in the transverse direction(TD),which was due to grain morphology and texture in these samples.The severity of Portevin-Le Chatelier(PLC)along the RD(0°)was much lower than that along the HD(45°)and TD(90°)owing to the presence of several strong orientations along the RD.By increasing the thickness reduction,the difference between strain hardening rates of RD,HD,and TD decreased due to the decrement of texture intensity.There was no difference between the fracture surfaces of 60%samples in the RD,HD,and TD,revealing nearly isotropic fracture behavior.
作者简介
Corresponding author:Roohollah JAMAATI,E-mail:jamaati@nit.ac.ir。
