Evolution, microhardness of ZrAlSi intermetallic and its impact on the elevated-temperature properties in Al-Si alloys

The influence of Si addition on the microstructures and properties of ZrAlSi intermetallics in Al-xSi-2Zr alloys was investigated. With Si addition increasing from 3 wt.% to 60%. ZrAlSi evolves from Zr(Al(1-m)Si(m))3 (0.10 <= m <= 0.21) to Zr(AlnSi1-n)2 (0.05 <= n <= 0.15). the content of Si in ZrAlSi and microhardness of the intermetallics increase synchronously. Besides, all the ZrAlSi intermetallics exhibit flake-like morphology. The effect of Zr addition and precipitation of ZrAlSi intermetallics on the elevated-temperature properties of an Al-Si piston alloy was investigated, and the tensile strength is increased by 3.8% with 0.11% Zr and decreased by 5.0% with 0.46% Zr addition, while the elongation and yield strength are increased by 13.0% and 6.9% with 0.11% Zr and decreased by 9.6% and 7.3% with 0.46% Zr addition, respectively. Crown Copyright (c) 2012 Published by Elsevier B.V. All rights reserved.