7050铝合金热压缩变形的流变行为及微观组织演变  

Characterization of Flow Behavior and Microstructural Evolution of 7050 Aluminum Alloy during Hot Compression Process

作　　者：陈修梵 彭小燕[2] 张慧颖[2] 肖丹[2] 王恒玉 徐国富[2,3] 

机构地区：[1]山东南山国家铝合金压力加工工程技术研究中心 [2]中南大学材料科学与工程学院 [3]中南大学有色金属材料科学与工程教育部重点实验室

出　　处：《特种铸造及有色合金》2015年第12期1237-1242,共6页Special Casting & Nonferrous Alloys

基　　金：国家民口配套项目(JPPT-115-2-948)

摘　　要：利用Gleeble-1500热模拟试验机对均匀化7050铝合金在573~723℃和0.000 5~1s-1变形条件下进行热压缩试验。通过线性回归分析计算出均匀化7050铝合金的应变硬化指数以及变形激活能,获得了均匀化7050铝合金热压缩变形条件下的流变应力本构方程。并借助扫描电镜（SEM）、电子背散射衍射（EBSD）和透射电镜（TEM）显微分析,对不同热变形条件下合金的微观组织演变进行研究。结果表明,均匀化7050铝合金在高温压缩变形过程中有动态回复和动态再结晶现象。随着变形温度升高和应变速率下降,合金位错密度降低,流变应力减小。在热变形过程中,合金的主要软化机制由动态回复逐渐演变为动态再结晶,热变形组织由位错亚结构转变为再结晶组织。Hot compression test of homogenized 7050 aluminum alloy was carried out on the Gleed-1500 thermal simulation machine at 573~723℃and 0.000 5~1s-1.The strain hardening coefficient and deformation activation energy of 7050 aluminum alloy were evaluated by linear regression analysis.And the flow stress constitutive equation of 7050 aluminum alloy during hot compression process was presenetd.The microstructure evolution of the alloy under different deformation conditions was observed using optical microscope（OM）,electron back scattered diffraction（EBSD）and transmission electron microscope（TEM）.The results reveal that dynamic recovery and dynamic recrystallization phenomenon can be observed during hot compression deformation process.And with increasing in the deformation temperature or decreasing in the strain rates,the flow stress and the dislocation density of homogenized7050 aluminum are decreased.The main softening mechanism of the alloy is characterized by from dynamic recovery to dynamic recrystallization during deformation.Correspondingly,microstructure is transformed from substructure of dislocation to recrystallized structure.

关 键 词：7050铝合金 热压缩变形 本构方程 微观组织演变 

分 类 号：TG146.21[一般工业技术—材料科学与工程]