Microstructure features of Cu-27.3%Mn alloy under laser rapid remelting and solidification condition

Laser rapid solidification experiments have been performed on Cu-27.3%Mn alloy to investigate the response of microstructure pattern and cellular spacing selection to the variation of growth rate. As growth rate increases, microstructure goes from light band to fine cell and absolute stability planar. Experimental results show that there exists a wide distribution range in cellular spacing under laser rapid solidification condition, the distribution range and the average spacing decrease with increase of the growth rate. The maximum, λ_max, minimum, λmin, and average primary spacing, λ̄, as functions of growth rate v_s, can be given by λ_max = 4.88v^0.26_s, λ_min = 2.35v^0.22_s and λ̄ = 3.66v^0.25_s, respectively. The experimental results are compared with the current KGT model for rapid cellular/dendritic growth, and a reasonable agreement is found.