DIMENSIONAL INSTABILITY OF LD31 Al ALLOY WELDMENTS AT ROOM TEMPERATURE AND AFTER THERMAL CYCLES
来源期刊：Acta Metallurgica Sinica2004年第1期
论文作者：X.S.Liu X.D.Sun W.L.Xu H.Y.Fang X.T.Tian
Key words：LD31 aluminum alloy; light interference; room temperature and thermal cycles; dimensional instability;
Abstract: The unstable dimensional distortion of LD31 aluminum alloy weldments at room temperature and after thermal cycles was studied by use of light interference and CMM(three-coordinate measuring machines). At the same time, distortion mechanism was analyzed from the viewpoint of mechanics and microstructure. Experimental results show that there exists obvious difference of unstable dimensional distortion between LD31 welded specimens under two conditions mentioned above. Under room temperature, dimensional variation of welded specimens will decrease gradually and finally tends to be stable during 200h after welding. The relative elongation of welded specimen is 3.0×10-5; After thermal cycles, distortion of welded specimen is much larger than that at room temperature. After 11 thermal cycles, the dimension will tend to be stable. Dimensional unstable distortion of weldments mainly results from temperature condition, microstructure variation and relaxation of welding residual stress.
X.S.Liu1，X.D.Sun2，W.L.Xu1，H.Y.Fang1，X.T.Tian1
(1.National key Laboratory of Advanced Welding Production and Technology, Harbin Institute of Technology,Harbin 150001, China;
2.Harbin First Mechanical Production Factory, Harbin 150080, China)
Abstract:The unstable dimensional distortion of LD31 aluminum alloy weldments at room temperature and after thermal cycles was studied by use of light interference and CMM(three-coordinate measuring machines). At the same time, distortion mechanism was analyzed from the viewpoint of mechanics and microstructure. Experimental results show that there exists obvious difference of unstable dimensional distortion between LD31 welded specimens under two conditions mentioned above. Under room temperature, dimensional variation of welded specimens will decrease gradually and finally tends to be stable during 200h after welding. The relative elongation of welded specimen is 3.0×10-5; After thermal cycles, distortion of welded specimen is much larger than that at room temperature. After 11 thermal cycles, the dimension will tend to be stable. Dimensional unstable distortion of weldments mainly results from temperature condition, microstructure variation and relaxation of welding residual stress.
Key words:LD31 aluminum alloy; light interference; room temperature and thermal cycles; dimensional instability;
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