铸铁表面激光熔敷层的抗裂性和耐磨性  

Crack resistance and wear resistance of laser clad layer on the surface of cast iron

作　　者：栾景飞[1] 严密[2] 周振丰[3] 

机构地区：[1]南京大学材料科学与工程系 [2]浙江大学 [3]吉林大学

出　　处：《材料研究学报》2003年第2期173-179,共7页Chinese Journal of Materials Research

基　　金：国家自然科学基金 No.50171065;教育部博士点基金 2000033507;留学归国人员基金[2000]367

摘　　要：采用免预热多道搭接的激光熔敷工艺,在铸铁表面制备出抗裂耐磨的激光熔敷层,研究了激光功率和扫描速度对熔敷层抗裂性的影响。适当的激光功率和扫描速度可以使铁基熔敷层的裂纹率最低。随着Ni含量的增加,熔敷层内奥氏体相体积分数增加;K可促进共晶碳化物团球化,熔敷层抗裂性增强。通过对铸铁表面激光熔敷层裂纹的萌生与扩展的动态观察,揭示了熔敷层开裂的微观机制。裂纹易在粗大渗碳体区或石墨与奥氏作的界面处萌生,奥氏体可明显抑制裂纹的扩展。Ti含量增加使熔敷层中原位自生的TiC的体积分数增大,熔敷层磨损质量损失减少,耐磨性增强。The cracking-resistant cladding materials on the surface of cast iron were prepared by laser cladding process without preheating treatment. The influence of laser processing parameters on the crack ratio of clad layer was investigated. The results show that there is a minimum value of crack ratio for laser power of 1500 W and a scanning speed of 400 mm/min. The iron-based cladding materials were used for verifying austenite volume fractions and cementite volume fractions of clad layer by adjusting Ni, K and Ti contents, and the effect of austenite volume fractions and nodulation of eutectic carbides on crack resistance of clad layers was investigated. The dynamic process of crack initiation and propagation of laser clad layer in cast iron was observed. Cracking mechanism of clad layer was revealed. The effect of endogenous TiC in the clad layer obtained by adjusting Ti contents on wear resistance of clad layer was studied.

关 键 词：金属材料 抗裂性 动态开裂 铸铁 表面激光熔敷层 耐磨性 表面处理 

分 类 号：TG174.44[金属学及工艺—金属表面处理] TG143[金属学及工艺—金属学]