热处理对选区激光熔化Co-Cr合金微观组织与力学性能的影响  

Effects of heat treatment on the microstructure and mechanical performance of Co-Cr alloy by selective laser melting

作　　者：张波[1] 刘艺[1] 夏书标 ZHANG Bo;LIU Yi;XIA Shubiao(Guiyang Vocational and Technical College,Guiyang 550081,China;College of Chemistry and Environmental Science,Qujing Normal University,Qujing 655011,Yunnan,China)

机构地区：[1]贵阳职业技术学院,贵阳550081 [2]曲靖师范学院化学与环境科学学院,云南曲靖655011

出　　处：《有色金属科学与工程》2024年第2期265-273,共9页Nonferrous Metals Science and Engineering

摘　　要：热处理不仅可以消除激光增材制造材过程中的热应力,还可以调控材料组织结构和力学性能。本文研究了选区激光熔化Co-Cr合金微观组织在不同热处理条件下的变化及其相应的力学性能。研究发现,打印态下合金组织为γ奥氏体,基体中存在大量层错和亚晶界组织,以及少量四方σ-CoCr沉淀相;在1150℃下保温1 h,发生γ-ε转变,ε马氏体含量为10.4%(V/V),同时沉淀相由四方σ相转变为六方Co_(3)W(Mo)_(2)Si相;再经过800℃处理2 h后,马氏体含量进一步增加至15.5%(V/V),同时沉淀相数量增加且尺寸增大。热处理后的沉淀相对力学性能影响显著,材料的硬度从31 HRC提高至38 HRC,屈服强度从848 MPa提高至1119 MPa。本研究可以为研究激光选区熔化Co基合金组织与性能调控提供参考。Heat treatment of laser additive manufactured materials cannot only eliminate thermal stress during the printing process,but also regulate their microstructure and mechanical properties.This article studies the changes in the microstructure of selective laser melted Co-Cr alloy under different heat treatment conditions and its corresponding mechanical properties.It was found that the alloy structure in the as-printed state wasγ-austenite,with a large amount of dislocation,sub-grain boundaries,and a small amount of tetragonalσ-CoCr precipitation phase in the matrix.Aγ-εtransformation occurred at 1150℃with a holding time of 1 h,and the volume fraction ofε-martensite was 10.4%.At the same time,the precipitation phase transformed from a tetragonalσ-phase to a hexagonal Co_(3)W(Mo)_(2)Si phase.After further treatment at 800℃for 2 h,the martensite content increased to 15.5%,and the quantity and size of the precipitation phase increased.The influence of the precipitation phase on the mechanical properties after heat treatment was significant.The material's hardness increased from 31 HRC to 38 HRC,and the yield strength increased from 848 MPa to 1119 MPa.This study can provide a reference for the microstructure and property regulation of Co-based alloys by selective laser melting.

关 键 词：选区激光熔化 Co-Cr合金 热处理 沉淀相 力学性能 

分 类 号：TG113[金属学及工艺—物理冶金]