Effect of the Production Parameters on Structural Features and Mechanical Properties of Multicomponent Creep-Resistant Niobium-Based Alloy

Abstract

The effect of key process parameters on the structural features and mechanical properties of the multicomponent creep-resistant 57Nb–10Cr–5Al–21Ti–7Mo (at.%) alloy produced by powder metallurgy methods from a mixture of elemental metal powders was studied. The production process included consolidation of the powder mixtures, part of which underwent mechanical activation in a planetary mill with subsequent hot forging. Some of the hot-forged samples were annealed in a vacuum furnace at 1600°C. The hot-forged materials exhibited a heterogeneous structure, consisting of a solid-solution matrix based on the Nb–Mo system and evenly distributed grains of an intermetallic phase based on the Ti–Al system, and were characterized by pronounced anisotropy. A gradient distribution of Al and Nb within the titanium grains after hot forging was revealed. Annealing at 1600°C altered the grain morphology and resulted in near-complete homogenization of the alloy with the formation of a single-phase bcc structure. The highest mechanical properties at room temperature and 600°C were observed for the materials produced by hot forging of a powder mixture ground for 30–60 min. At 1000°C, the yield stress of the alloy annealed at 1600°C exceeded σ_0.2 of the hot-forged alloys not subjected to annealing and reached the level of the as-cast alloy of the same composition.