功能梯度Al_2O_3涂层残余热应力分析  

Simulation of Residual Stresses in Functionally Gradient Al_2O_3 Coatings

作　　者：刘红兵[1] 陶杰[1] 张平则[1] 常华[1] 

机构地区：[1]南京航空航天大学材料科学与技术学院,南京210016

出　　处：《机械工程学报》2008年第8期26-32,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金(50571045);江苏省科技成果转化专项资金(BA2006067)资助项目

摘　　要：Al_2O_3/316L功能梯度材料是一种聚变反应堆第一壁的候选材料。为避免制备过程中因材料之间热物理性能差别产生的热应力过大造成材料的失效,须对梯度材料进行合理的热应力缓和设计。运用有限元软件,分析成分分布指数、梯度涂层厚度和梯度层数目等参数对Al_2O_3/316L功能梯度材料残余热应力的影响。分析结果表明:体积分布指数p=1.0时所受热应力最小,涂层承受压应力作用;梯度层数为9时热应力缓和效果最好;梯度层厚度不宜过大;将非功能梯度材料与优化后的功能梯度材料的残余热应力进行比,结果显示:功能梯度材料缓和热应力效果十分显著。最后利用等离子喷涂方法制备了梯度涂层测试涂层残余应力,并与有限元结果进行对比,以验证模拟的准确性。Al2O3/316L functionally graded material （FGM） is a potential candidate for plasma facing material used in a thermonuclear device. The finite element method is used to analyze thermal stresses during the preparation of Al2O3/316L FGM in order to reduce thermal expansion mismatch among the different coating layers and substrate. The effects of compositional exponent, the coating thickness and the number of graded layers on the residual stresses are analyzed by using finite element software. The results show that all components are subjected to the minimum thermal stresses and the coating endures the action of compressive stress when the compositional gradient exponent p= 1.0. Moreover, the effect of thermal stress mitigation is best when n=9. It is also indicated that gradient layer thickness should not be too large. Compared with non-functionally gradient material （NFGM）, the optimized FGM exhibits an outstanding effect in the mitigation of thermal stresses. Al2O3 gradient coating is fabricated on the surface of 316L stainless steel with the aid of plasma spraying. The residual stresses at the different positions of Al2O3 coating are measured by X-ray diffi＇action approach to verify the reliability of the simulation.

关 键 词：聚变堆材料 功能梯度材料 残余热应力 有限元分析 

分 类 号：TB33[一般工业技术—材料科学与工程] TL33[核科学技术—核技术及应用]