Microstructure and hardness investigation of 17-4PH stainless steel by laser quenching
Microstructure and hardness investigation of 17-4PH stainless steel by laser quenching
复制标题
DOI：
10.1016/j.msea.2011.12.004
复制
发表时间：
2012-02
期刊：
影响因子：
6.4
通讯作者：
Zhaoyun Chen;Guijuan Zhou;Z. Chen
中科院分区：
文献类型：
--
作者：
Zhaoyun Chen;Guijuan Zhou;Z. Chen
采用5 kW连续波CO2激光器对17-4PH钢进行了激光相变硬化处理。利用光学显微镜、透射电镜和57 Fe穆斯堡尔谱仪研究了激光淬火样品的微观结构。通过维氏硬度计测定硬度分布。硬化层厚度约为1.75mm，由典型的板条马氏体、粗大的NbC和大量细小的面心立方富铜相组成。硬化区的最大硬度值为446 HV，比基体的硬度值（386- 397 HV）高50 HV。17-4PH钢激光相变层硬度较高的原因是：基体位错密度高，组织细小，fcc富铜相细小，类似于Al-Cu析出相，残余奥氏体转变为板条马氏体。
Surface hardening of 17-4PH was achieved by laser transformation hardening using 5kW continuous wave CO2laser system. The microstructure of the laser-quenched sample was investigated by optical microscopy, transmission electron microscope and57Fe Mössbauer spectrometer. The hardness profile was determined by a Vickers hardness tester. The hardened layer with a thickness of 1.75mm was formed, and it was composed of classic lath martensite, coarse NbC and a lot of finer fcc copper-rich phases which were similar to ɛ-Cu precipitates. The maximal hardness value of hardened zone is 446HV which is 50HV higher than that of the substrate (386–397HV). The higher hardness in laser transformation layer of the 17-4PH steel could be attributed to the following aspects: the matrix with a high dislocation density; the fine microstructure; the finer fcc copper-rich phases that were similar to the ɛ-Cu precipitates as well as the transforming of retained austenite into lath martensite.