Morphological evolution of ZrAlSi phase and its impact on the elevated-temperature properties of Al-Si piston alloy

It is investigated that the morphologies of ZrAlSi phase in Al-18Si-xZr alloys will evolve from flake-like to block-like with increasing Zr content and the precipitation of the ZrAlSi intermetallic decreases the volume fraction of primary Si phase. The effect of flake-like and block-like ZrAlSi phase on the microstructure and elevated-temperature mechanical properties of an Al-Si multicomponent piston alloy was also investigated. It was found that flake-like ZrAlSi particles lead to a decrease of 7.28%, 3.23% and 8.85% for the elevated-temperature tensile strength, elongation and yield strength of the piston alloy, respectively, whereas block-like particles cause an increase of 15.82%, 12.94% and 14.75%, respectively. Meanwhile, the linear expansion is almost unaffected. (C) 2013 Elsevier B. V. All rights reserved.