激光快速凝固条件下Cu-31.4%Mn合金的微观组织特征

利用连续波CO2激光器对Cu 314%Mn进行了系列表面熔凝实验，对该合金的组织形态和胞晶间距选择规律进行了研究.结果表明：随着生长速度的提高，组织形态由低速平界面向展宽胞晶、规则胞晶、展宽胞晶、类平面晶和高速绝对稳定平界面转变.在快速凝固条件下，Cu 314%Mn合金的胞晶间距存在一个选择范围，最大、最小和平均胞晶间距与生长速度的关系分别为λmax=682v-033s，λmin=289v-028s和=435v-031s，实验结果与Hunt Lu模型的预测结果相吻合.

Microstructure characteristics of Cu-31.4%Mn alloy under laser rapid solidification condition

Laser rapid solidification experiments have been performed on Cu 31.4%Mn alloy to investigate the response of microstructure pattern and cellular spacing selection to the variation of growth rate.With increasing growth rate,microstructures go from light band to elongated cell,regular cell,then elongated cell and planar like structure,and finally to absolute stability planar in turn.Experimental results show that there is a distribution range in cellular spacing under the aser rapid solidification condition,the distribution range and the average spacing decrease with the increase of the growth rate.The maximum,λmax, minimum,λmin,and average primary spacing,A,as functions of growth rate vs, can be given by λmax=682v-033s，λmin=289v-028s and =435v-031s,respectively.The experimental results are compared with the Hunt Lu numerical model for rapid cellular/dendritic growth,and a reasonable agreement is found.