Heat-resistant magnesium-based alloys for aircraft casting

Abstract

The necessity of increasing the mechanical properties and heat resistance of aviation magnesium case casting is demonstrated. The choice of alloying elements to improve the installation characteristics of the Mg-Al-Zn system is justified. It was found that Ti, Zr and Hf additives in the ML5 alloy in an amount from 0.05 to 1.0 mass. % contribute to reducing the distance between the axes of the dendrites of the 2nd order up to 1.5 times and the size of the micrograin - up to 2 times.
The influence of the morphology and topology of the structural components of magnesium alloys on their properties is demonstrated. It was found that microalloying of magnesium alloys Ti, Zr and Hf in an amount  from 0.05 to 0.1 mass. % increases the volume percent of intermetallic compounds, displacing them towards smaller size groups with the simultaneous formation of spherical intermetallic compounds located in the center of the grain and serving as additional crystallization centers.
It has been established that microalloying of magnesium alloys with refractory metals leads to the formation of complex intermetallic phases enriched with the corresponding alloying elements. It is shown that the optimal additives Ti, Zr and Hf in an amount  from 0.05 to 0.1 mass. % help increase strength by ~ 25%, ductility by ~ 2.5 times, and heat resistance by ~ 2 times.
New heat-resistant magnesium alloys with a high complex of mechanical properties and heat resistance have been developed. An industrial testing of the production technology of castings made of improved magnesium alloy was carried out in the conditions of the enterprise JSC “Motor Sich”. The use of developed magnesium alloys will improve the reliability and operation safety of aircraft engines.