钴基合金-不锈钢梯度强化材料低应力多碰塑变分析  

Low-stress Multi-touch Plastic Deformation Analysis of Cobalt-based Alloy-Stainless Steel Gradient Reinforcement Materials

作　　者：赵晔婷 石世宏[1] 傅戈雁[1] 

机构地区：[1]苏州大学机电工程学院,江苏苏州215021

出　　处：《表面技术》2015年第2期68-72,98,共6页Surface Technology

基　　金：国家自然科学基金项目(11172191);江苏省科技支撑计划(BE2012068)~~

摘　　要：目的研究钴基合金-不锈钢梯度强化材料抵抗低应力多碰塑性变形的能力,以改善单一涂层应力集中问题。方法制备指数梯度和线性梯度涂层试样,与304不锈钢基体试样一起进行低应力多碰实验,比较分析3种材料的塑性变形量、硬度变化量与金相组织变化。结果线性梯度涂层试样的累积塑性变形量约为304不锈钢的1/2,指数梯度涂层试样的累积塑性变形量约为304不锈钢的1/3;两种涂层试样均存在循环硬化及软化现象,硬度值由表及里逐渐减小,多碰后塑性变形符合"趋表效应"。结论两种梯度涂层强化材料的抗低应力多碰塑变能力均明显优于未强化材料,且指数梯度强化材料性能优于线性梯度强化材料。Objective To study the resistance of Cobalt-based alloy- stainless steel gradient reinforcement materials against lowstress multi-touch plastic deformation,in order to improve the stress concentration problem of single coating. Methods The samples were prepared by laser cladding Cobalt-based alloy powder with exponential and linear weight fraction on substrates. Low-stress multi-touch experiment was conducted against the 304 stainless steel substrate. The plastic deformation,hardness and microstructure of all coatings were analyzed and compared in details. Results The cumulative plastic deformation of the sample with addition of linear gradient weight fraction Cobalt-based alloy powder was reduced by about 50% compared to the 304 stainless steel substrate,while the cumulative plastic deformation of the sample with addition of exponential gradient weight fraction Cobalt-based alloy powder was reduced by about 67% compared to the 304 stainless steel substrate. Although cyclic hardening and cyclic softening phenomena existed in both Cobalt-based gradient reinforced samples,the overall variation trend of the micro-hardness was that micro-hardness values gradually decreased from the surface to the substrate. Besides,the plastic deformation of reinforced materials conformed to ＂ skin effect＂ after multi-touch. Conclusion The resistance of both gradient reinforced coatings against low-stress multi-touch plastic deformation was much better than that of the substrate without reinforcement,and the properties of exponential gradient reinforced samples were better than those of the linear reinforced samples.

关 键 词：低应力多碰 塑变 梯度强化 趋表效应 

分 类 号：TG174.445[金属学及工艺—金属表面处理]