Development of High Temperature Die-Cast Magnesium Alloys for Small IC Engine Application

Abstract

An innovative and superior coarsening/creep resistant Al-based ternary short-range order (SRO,0–2nm)/cluster(2–10nm) at critically high temperature and stress of 300°C/50MPa was proposed and verified in Mg, and a highly heat-resistant die-cast Mg alloy was thus successfully developed with the super low steady-state creep rate (1.35×10−10s−1) and long creep life (>600h) under the critical condition of 300ºC/50MPa. This work changes the common belief of the detrimental effect of Al on the high temperature creep of Mg alloys over the past few decades, and it provides key evidence for the long-term and massive existence of SRO/clusters in Mg alloys under critically high temperatures and stresses. It greatly increases the working temperature of die-cast Mg alloys from 120-200°C to 300-350°C. The developed alloy has been transferred into manufacturing high temperature (300-350°C) Mg components used in small internal combustion (IC) engines.