纯镍的高温塑性变形行为及本构方程  

High Temperature Plastic Deformation Behavior and Constitutive Equation of Pure Nickel

作　　者：张兵[1] 朱乐乐[1] 王快社[1] 王文[1] 郝亚鑫 

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710055

出　　处：《稀有金属》2015年第5期406-413,共8页Chinese Journal of Rare Metals

基　　金：陕西省教育厅产业化项目(2011GJ11)资助

摘　　要：利用Gleeble-3800热模拟试验机,采用正交实验的方法,进行了单道次压缩试验,研究了纯镍N6板材在不同变形温度和不同应变速率条件下的大变形量热变形行为。结果显示,纯镍N6板坯在大的应变量条件下,出现了稳态流变之后,流变应力再升高的现象;在应变速率一定的条件下,流变应力随变形温度的升高而降低;在相同的变形温度条件下,流变应力随应变速率的增大而增大。说明流变应力与变形温度和应变速率的关系敏感。在变形速率为40 s-1时,流变应力曲线失稳,呈波浪形,说明在较大的应变速率条件下,纯镍N6板材呈现明显的流变失稳特征。并对实验测得的数据进行线性回归,得出双曲正弦函数形式本构方程中的材料参数,将材料参数对应变进行二次拟合,建立了纯镍N6板坯热变形过程中流变应力与变形温度、应变速率及应变的本构关系。经验证,所建立的本构关系能够很好地反应纯镍N6板坯的实际热变形行为特征。Severe deformation behaviors of pure nickel N6 plate under different temperatures and deformation rates were investigated by single press test on the Gleeble-3800 thermo mechanical simulation through orthogonal experiment. The results showed that the flow stress of the plate under the severe deformation increased again after the appearance of steady flow stress; with the rise of deformation temperature, the flow stress went down under the same deformation rate ; with the rise of deformation rate, the flow stress went up under the same temperature, which indicated the sensitive relationship of flow stress with deformation temperature and strain rate. With the deformation rate of 40 s - 1 , the flow stress curve became instable and undulated, which showed that under the condition of large strain rate, pure nickel N6 plate had obvious rheological instability characteristics. The linear regression was carried out with experimental data, and the hyperbolic sine function material parameters of the constitutive equation of style were obtained, and then the strain was quadratic fitted with the material parameters, and constitutive equations of flow stress, deformation temperature, deformation rate, and the strain for the pure nickel N6 plate during hot deformation were built. As verified, the constitutive equations were able to reflect the characteristics of the real deformation of the pure nickel N6 plate.

关 键 词：纯镍 热压缩变形 流变应力 本构方程 

分 类 号：TG146.15[一般工业技术—材料科学与工程]