Microstructure evolution of laser rapidly solidified Al-Mn alloys  

作　　者：YANG Sen, HUANG Weidong, LIU Wenjin and ZHOU Yaohe(1. Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China 2. Department of Materials Science and Engineering, Inner Mongolia Polytechnic University, Hohhot 010062, China 3. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China) 

出　　处：《Progress in Natural Science:Materials International》2002年第9期684-688,共5页自然科学进展·国际材料（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 59771054); Postdoctoral Science Foundation of China, and Postdoctoral Science Foundation of Tsinghua-Zhongda.

摘　　要：A series of laser surface remelting experiments of Al-1.1, 3.2 and 5.6 wt% Mn alloys has been conducted using a 5 kW CW CO2 laser, and the microstructures of samples have also been investigated. The experimental results show that no apparent eutectic growth appears in the whole growth rate range for Al-3.2 wt% Mn alloy under laser rapid solidification condition, and the microstructure grows in the form of α(Al) cell/dendrite. With the increase of growth rate, the microstructures of Al-5.6wt%Mn alloy change from Al6Mn dendrite to α(Al) +Al6Mn eutectic, α(Al) cellular/dendrite and segregation-free solid solution. The critical rates of Al-1.1, 3.2 and 5.6 wt% Mn alloys to attain absolute stability are 44.1, 134.6 and 230.1 mm/s respectively, and a reasonable agreement has been found between the experimental results and those calculated according to Mullins-Sekerka's theory.A series of laser surface remelting experiments of Al-1. 1, 3. 2 and 5. 6 wt % Mn alloys has been conducted using a 5 kW CW CO2 laser, and the microstructures of samples have also been investigated. The experimental results show that no apparent eutectic growth appears in the whole growth rate range for Al-3.2 wt% Mn alloy under laser rapid solidification condition, and the microstructure grows in the form of alpha( Al) cell/dendrite. With the increase of growth rate, the microstructures of Al-5. 6wt% Mn alloy change from Al6Mn dendrite to alpha(Al) + Al6Mn eutectic, alpha(Al) cellular/ dendrite and segregation- free solid solution. The critical rates of A.1-1. 1, 3. 2 and 5. 6 wt % Mn alloys to attain absolute stability are 44. 1, 134. 6 and 230. 1 mm/s respectively, and a reasonable agreement has been found between the experimental results and those calculated according to Mullins-Sekerka's theory.

关 键 词：LASER rapid solidification  AL-MN alloys  ABSOLUTE stability. 

分 类 号：TG146.21[一般工业技术—材料科学与工程]