(1. 重庆理工大学 材料科学与工程学院，重庆 400054； 2. 重庆理工大学 重庆市模具技术重点实验室，重庆 400054)
摘 要: 研究保温时间、冷却速度以及预变形对金属钴γ→ε相变行为的影响。重点使用电子背向散射衍射技术表征γ→ε转变的微观组织及织构演变行为。结果表明，经过γ→ε转变后金属钴的微观组织结构为双相组织(γ相和ε相)：γ相中存在Σ3特殊晶界，ε相中存在70.5°/á ？特殊晶界；且由于这些特殊晶界的存在，导致晶粒细化和基面织构弱化。保温时间和冷却速度对残余奥氏体(γ相)，Σ3晶界以及70.5°/á ？晶界含量的影响，不存在明显的规律。然而，随着预变形程度的增加，奥氏体含量、Σ3晶界和70.5°/á ？晶界的含量都随之增加，且晶粒细化及织构弱化效应显著。对γ→ε相变后板条组织的表征，发现不同形态特征的板条组织可由块状和三角形为基本单元所构成。
关键字: 钴金属；γ→ε相变；显微组织；电子背向散射衍射技术
（1. School of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400054, China; 2. Chongqing Municipal Key Laboratory of Institutions of Higher Education for Mould Technology Chongqing University of Technology, Chongqing 400054, China）
Abstract:The effect of holding time, cooling rate and predeformation on microstructural characteristics of a cobalt (Co) undergoing γ→ε transformation was investigated. The microstructural characteristics and texture evolution during γ→ε transformation were analysed by using electron backscatter diffraction equipped in field emission gun scanning electron microscope. The results show that a dual-phase microstructure (γ phase and ε phase). Σ3 boundaries exist in γ phase and special boundaries with misorientation (70.5°/á ？) are observed ε phase. Refining grain size and weakening basal texture are via Σ3 boundaries and 70.5°/á ？ boundaries. There are no obvious regularity for the effects of holding time and cooling rate on the amounts of the retained austenite, 70.5°/á ？boundaries and Σ3 boundaries. However, the predeformation extent markedly affects the amounts of the retained austenite, 70.5°/á ？ boundaries, Σ3 boundaries, grain refinement and texture weaken. The morphology characteristics of plate-like products are consisted of the blocky units and the triangle units.
Key words: cobalt; γ→ε transformation; microstructural characteristics; electron backscatter diffraction
