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研究了激光重熔工艺参数对三种不同成分的Cu Mn合金重熔区微观组织生长方向的影响。结果表明 ,熔池中微观组织的生长方向强烈地受激光工艺参数 (激光输出功率和扫描速度 )和合金成分的影响。通过选择合适的工艺参数 ,实现了与Bridgman法类似的超高温度梯度快速定向凝固 ,其温度梯度可高达 10 6 K m ,速度可高达 2 4mm s。利用激光表面熔凝技术实现超高温度梯度快速定向凝固的关键在于 :1)在激光熔池内获得与激光扫描速度方向一致的温度梯度 ;2 )根据合金凝固特性选择适当的激光工艺参数以获得胞晶组织。
The effects of laser remelting parameters on the microstructure growth of Cu Mn alloys in three different compositions were studied. The results show that the growth direction of the microstructure in the weld pool is strongly affected by the laser process parameters (laser output power and scanning speed) and alloy composition. Through the selection of appropriate process parameters, the ultrahigh temperature gradient similar to the Bridgman method can be rapidly directionally solidified with a temperature gradient of up to 10 6 K m and a speed of up to 24 mm s. The key to realize the ultra-high temperature gradient rapid solidification by using the laser surface melting technique lies in: 1) obtaining a temperature gradient consistent with the laser scanning speed in the laser melting pool; 2) selecting suitable laser processing parameters according to the solidification property of the alloy to obtain cells Crystal organization.