Co-Cr-Nb-W合金碳化物组织转变及力学性能研究
Carbides Evolution and Mechanical Behavior of Co-Cr-Nb-W Alloy
凌晨 1李尚平 2林筠 3侯杰 2李义平 3骆合力2
作者信息
- 1. 钢铁研究总院高温材料研究所,北京 100081
- 2. 北京钢研高纳科技股份有限公司,北京 100081
- 3. 中国航发贵阳发动机设计研究所,贵州贵阳 550081
- 折叠
摘要
热处理过程中的碳化物转变对高温合金的力学性能影响显著.采用XRD、SEM、EPMA、TEM等研究了Co-Cr-Nb-W耐磨合金热处理过程中碳化物的析出类型、分布特征、演变机制及其对高温拉伸性能的影响.Co-Cr-Nb-W耐磨合金主要在钎焊和时效热处理后使用,该过程中主要发生如下2个碳化物转变过程:MC+matrix=M6C和M23C6+matrix=M6C.合金在高温拉伸应力下的断裂机制为韧脆混合机制,块状初生碳化物与基体之间的界面容易成为裂纹萌生源.热处理过程消除了容易引起晶界迁移的片层状共晶M23C6,在骨架状MC周围析出了细小的M6C,同时改善了枝晶间元素偏析,促进基体中形成高密度的交叠层错带,使得合金在1000 ℃下的抗拉强度提高约20 MPa.
Abstract
Carbides transformation during heat-treatment process has a significant effect on the mechanical properties of superalloys.The distribution and evolution mechanism of carbides and their effects on high-temperature tensile properties of Co-Cr-Nb-W wear-resistant alloy during heat treatment process were investigated by XRD,SEM,EPMA,and TEM.There are two carbides transformation processes in the Co-Cr-Nb-W alloy during brazing simulation and aging:MC+matrix=M6C and M23C6+matrix=M6C.The fracture mechanism of the Co-Cr-Nb-W alloy under high temperature tensile stress is a hybrid mechanism of ductile fracture and brittle fracture,and the interface between the bulk primary carbide and the matrix is easy to become the source of crack source.The heat treatment process eliminates the lamellar M23C6,which is easy to cause grain boundary migration,induces the precipitation of fine M6C particles around the skeleton MC,improves the interdendritic element segregation,promotes the formation of high-density overlapping stacking fault bands in the matrix,and increases the tensile strength of the alloy at 1000 ℃ by about 20 MPa.
关键词
钴基高温合金/碳化物转变/热处理/高温拉伸性能/高温耐磨材料Key words
cobalt-based superalloy/carbides transformation/heat treatment/high-temperature tensile property/wear-resistant alloy引用本文复制引用
基金项目
国家重点研发计划(2022YFC3902002)
出版年
2024
NETL
NSTL
万方数据