(1. 重慶理工大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400054； 2. 重慶理工大學(xué) 重慶市模具技術(shù)重點(diǎn)實(shí)驗(yàn)室，重慶 400054)
摘 要: 研究保溫時(shí)間、冷卻速度以及預(yù)變形對(duì)金屬鈷γ→ε相變行為的影響。重點(diǎn)使用電子背向散射衍射技術(shù)表征γ→ε轉(zhuǎn)變的微觀組織及織構(gòu)演變行為。結(jié)果表明，經(jīng)過(guò)γ→ε轉(zhuǎn)變后金屬鈷的微觀組織結(jié)構(gòu)為雙相組織(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；且由于這些特殊晶界的存在，導(dǎo)致晶粒細(xì)化和基面織構(gòu)弱化。保溫時(shí)間和冷卻速度對(duì)殘余奧氏體(γ相)，Σ3晶界以及70.5°/á ？晶界含量的影響，不存在明顯的規(guī)律。然而，隨著預(yù)變形程度的增加，奧氏體含量、Σ3晶界和70.5°/á ？晶界的含量都隨之增加，且晶粒細(xì)化及織構(gòu)弱化效應(yīng)顯著。對(duì)γ→ε相變后板條組織的表征，發(fā)現(xiàn)不同形態(tài)特征的板條組織可由塊狀和三角形為基本單元所構(gòu)成。
關(guān)鍵字: 鈷金屬；γ→ε相變；顯微組織；電子背向散射衍射技術(shù)
（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
