【作者】 任榕； 吴玉程； 汤文明； 汪峰涛； 郑治祥；

【Author】 REN Rong WU Yu-cheng TANG Wen-ming WANG Feng-tao ZHENG Zhi-xiang (School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China)

【机构】 合肥工业大学材料科学与工程学院；

【摘要】 利用 XRD 和 TEM 研究机械合金化及等温退火过程中 Fe₃₅Al₃₅Ti₁₅C₁₅（摩尔分数,%）元素混合粉的结构演变和晶粒生长动力学,讨论其晶粒生长机制。结果表明:该元素混合粉在球磨过程中首先形成 Fe（Al, Ti,C）和 Ti（C）固溶体,随后 Ti 和 C 从 Fe（Al,Ti,C）中析出,并与 Ti（C）反应逐渐形成非化学计量的化合物 TiC_1-x。球磨终产物为纳米晶 Fe（Al）及 TiC_1-x组成相;在机械合金化粉体的热处理过程中,球磨70 h 后粉体发生组成相结构有序化转变,即由无序的 Fe（Al）固溶体向有序的 B2-FeAl 金属间化合物转变,同时 TiC_1-x化合物转变成等比化合物 TiC。根据晶粒生长动力学理论计算 FeAl 晶粒生长激活能为966.9 kJ/mol,晶粒生长受到明显的抑制,原位 TiC/FeAl 基纳米复合材料粉体的热稳定性较高。更多还原

【Abstract】 Both the structural evolutions of Fe₃₅Al₃₅Ti₁₅C₁₅ （mole fraction,%） elemental powder during mechanical alloying,and the structural evolutions and grain growth kinetics of the mechanically alloyed Fe₃₅Al₃₅Ti₁₅C₁₅ powder during annealing were investigated by XRD and TEM.The grain growth mechanism was also discussed.The results show that Fe（Al,Ti,C） and Ti（C） solid solution are firstly formed during milling the Fe₃₅Al₃₅Ti₁₅C₁₅ elemental powder. With increasing milling time,the Ti and C elements precipitate from Fe（Al,Ti,C）,and react with Ti（C） to form nonstoichiometric TiC_1-x compound.The final products of the MA process are nanocrystalline Fe（Al） and TiC_1-x.The disordered Fe（Al） transforms into the ordered B2-FeAl phase during the heat treatment of 70 h milled powder.Meanwhile, TiC_1-x are completely transformed into stoichiometric TiC.The activation energy for the nanocrystalline FeAl growth is calculated to be 966.9 kJ/mol according to the kinetics theory of nanocrystalline growth.The grain growth of FeAl is significantly inhibited.The in-situ TiC/FeAl nanocomposite has high thermal stability.更多还原