Investigation on WC–Al composite coatings of AZ91 alloy by mechanical alloying

Abstract

In this paper, WC–Al composite coatings of AZ91 alloy prepared by mechanical alloying have been investigated in detail. It was found that the premixing process of composite powders has no significant effect in promoting the formation of uniform coating of WC–Al powders. Under the optimised conditions, i.e. the composition of composite powders of (10 g WC–6·5 g Al–3 g AZ91–0·5 g Mg), ball-to-powder weight ratio of 14∶1 and milling duration of 12 h, the average thickness of composite coating can be remarkably increased to 38·01 μm. Compared with the bare substrate, the Brinell hardness of the specimen with WC–Al composite coating can be significantly increased by about 90·01.