Effect of warm rolling on microstructure, porosity, and hardness of a spray-formed LM25 aluminum alloy


The LM25 aluminum alloy was obtained using the spray deposition method at an optimum pressure of approximately 10 bar, a deposition distance of approximately 41 cm. and an inclination angle of 0º. The central portion of the spray deposit was warm rolled to obtain various thickness reductions, i.e., 0%, 20%, 40%, 60%, and 80% at 100ºC; it was found that the number of pores decreased as the thickness reduction increased. It was observed that the fine microstructure and secondary phase in the samples with a larger percentage of thickness reduction was due to the expediting cooling and freezing rate of the molten metal. The porosity and mechanical properties were better in the spray deposited and warmed rolled LM 25 substrate than the cast LM25 alloy.