Elastoplastic response of functionally graded cemented carbides due to thermal loading  

热载荷下梯度结构硬质合金的弹塑性响应(英文)

作　　者：黄自谦[1,2] 李传新[3] 

机构地区：[1]东南大学物理系,南京211189 [2]广西师范学院物理系,南宁530001 [3]荆楚理工学院数理学院,荆门448000

出　　处：《Journal of Southeast University(English Edition)》2013年第4期463-466,共4页东南大学学报（英文版）

基　　金：The National Natural Science Foundation of China(No.50323008,31070517);Scientific Research Foundation of Guangxi Education Department(No.201203YB097)

摘　　要：Finite dement formulations are used to simulate the evolution of the elastoplastic response of functionally graded cemented carbides （FGCC） due to thermal loading. The geometry of specimens is an axisymmetric solid cylinder with a two-dimensional gradient. The elastoplastic constitutive relationship is developed by constraint factors. Numerical results show that compressive stresses occur in the surface zone and tensile stresses in the cobalt rich zone when the temperature drops from the initial stress-free temperature of 800 to 0℃. The maximum value of the surface compressive stress is 254 MPa and the maximum value of the tensile stress is 252 MPa in the cobalt rich zones. When the cobalt concentration difference in the specimens is equal to or greater than 0.3, there is pronounced plastic flow in cobalt rich zone. When the temperature heats up from 0 to 800 ℃, the total plastic strain reaches 0.001 4. Plastic flow has a significant effect on the reduction of thermal stress concentration.采用有限元方法模拟了热载荷下梯度结构硬质合金的弹塑性响应.样品几何模型为二维梯度结构的轴对称圆柱体.通过引入约束因子构建了梯度材料的弹塑性本构方程.数值模拟表明:当材料温度从初始无应力的800℃下降到0℃时,在样品表面出现了压应力而在富钴区出现了拉应力;表面压应力的最大值为254 MPa,富钴区拉应力的最大值为252 MPa;在钴相浓度差等于或大于0.3时,钴相梯度区出现了明显的塑性流动;当温度从0℃上升到800℃时,总的塑性应变达到0.001 4.塑性流动有利于降低材料内部的热应力集中.

关 键 词：functionally graded cemented carbides finite element method constraint factors elastoplastic response 

分 类 号：TB383[一般工业技术—材料科学与工程]