Microstructure and high-temperature strength in Cr–Si binary alloys

Abstract

The microstructure and high-temperature strength in Cr–Si alloys with different Si contents were investigated by SEM and a compression test. Cr–10Si and Cr–13Si alloys have a two-phase microstructure composed of CrSS and Cr3Si, and the morphology depends on the Si content. The 0.2% proof stress evaluated at 1000 °C increases with increasing Si content to 15 at%, and the incremental amount becomes drastically larger in the composition range of 10–13 at% Si. The optimal Si content in the balance of strength and ductility is about 13 at%. The 0.2% proof stress at 1000 °C in a Cr–13Si alloy with a low density (6.68 g･cm−3) is higher than that of a Ni-based superalloy, Mar-M247, and the specific strength is roughly twice as high as that in the Mar-M247.