Comparative Study of the Structure and Mechanical Properties of PM HIP Compacts Manufactured Using Rapidly Quenched PREP Powder and a Product Made Using Traditional Technology from a Heat-Resistant Titanium-Based Alloy

Abstract

A comparative study of the structure of PM HIP compacts made using spherical particles (granules) of rapidly quenched PREP powder of a heat-resistant α+β Ti-based alloy and a similar product manufactured using traditional technology has been carried out. Multi-scale study of the microstructure of PM HIP compacts and an analogous product manufactured using traditional technologies has been performed by metallography, SEM, TEM, EDX, and OIM. The influence of vacuum heat treatment and temperature consolidation of HIP in the regions of (α+β) and β phases on the regularities of the structure formation of PM HIP compacts of the heat-resistant titanium-based alloy has been revealed. Features of microstructures such as lamellar, bimodal microstructure and grains have been detected and studied in detail in PM HIP compacts and in a product obtained by traditional technology. The extreme behavior of the partition ratio k_d of alloying elements between the α and β phases in the product obtained using traditional technology, in comparison with PM HIP compacts, has been discovered and studied in detail. Analysis of the obtained result, in comparison with the results of a comparative study of the structure and properties of PM HIP compacts obtained using rapidly quenched PREP powders and products obtained using traditional technology from stainless steels and Ni based superalloys, has allowed the following important conclusion. The cooling rate during solidification is the dominant factor in the formation of the final structural-phase state (composition of α and β phases in the Ti alloy) and, therefore, is a key hereditary technological parameter that determines the structural-phase state and the increased level of mechanical properties of PM HIP compacts compared to the product obtained using traditional technology.