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Investigation has been made on the causes of hot cracking in the surfacing layer of Ni_3Al base alloy by analysing the solidification process of fusion pool and the distribution of thermal stresses.The results show that the cracking is directly related to both the occurrence of eutectic phase β’(NiAl) within the interdendritic region and high thermal stresses in the surfacing layer,and which are caused by selecting high welding rate.When the process of electric arc weld is changed from straight line movement to that along’Z’pattern,the cracking in the surfacing layer of Ni_3Al base alloy is prevented owing to being reduced of both the cooling rate of liquid in the fusion pool and the speed of the moving heat source.Lowering the output power of the electric arc welding could lead to the reducing of melting volume of the base material,and lower the amount of iron atoms dissolving in the fusion pool,so that the trend of the eutectic reaction within the interdendritic region is reduced,and which is helpful to suppress the cracking in the surfacing layer of Ni_3Al base alloy.
Investigation has been made on the causes of hot cracking in the surfacing layer of Ni_3Al base alloy by analysing the solidification process of fusion pool and the distribution of thermal stresses. The results show that the cracking is directly related to both the occurrence of eutectic phase β ’(NiAl) within the interdendritic region and high thermal stresses in the surfacing layer, and which are caused by selecting high welding rate .When the process of electric arc weld is changed from straight line movement to that along’Z’pattern, the cracking in the surfacing layer of Ni 3 Al base alloy is prevented due to being reduced of both the cooling rate of liquid in the fusion pool and the speed of the moving heat source. Powering the output power of the electric arc welding could lead to the reducing of melting volume of the base material, and lower the amount of iron atoms dissolving in the fusion pool, so that the trend of the eutectic reaction within the interdendritic region is reduced, an d which is helpful to suppress the cracking in the surfacing layer of Ni_3Al base alloy.