Effect of Heat Treatment on the Microstructure Development of TC21 Alloy

Abstract

The microstructure development of TC21 alloy after double α/β solution and aging heat treatment was investigated. Results show that primary α phase morphology is determined by the first solution treatment at the top of α/β portion. Varying the cooling rates can significantly influence the volume fraction of retained β phase and secondary α phase. Higher cooling rate results in greater retention of the β phase and transformation of the phase into secondary α phase upon aging. This higher amount of fine secondary α phase causes higher strength and lower toughness. Second α/β heat treatment temperature remarkably influences the heat treatment response of the microstructure. Higher heat treatment temperature keeps greater amounts of β with fine transformed α in the final microstructures. Lower α/β heat treatment temperature results in less responsive retained β during aging process. Aging treatment leads to decomposition of retained β phase, particularly in larger retained β regions that exhibit lower stability.

Study on Microstructure and Properties of Additive-Manufactured TC4ELI+TC21 Titanium Alloy Gradient Composite Structures

“…TC21 titanium alloy is a new type of high-strength, high-toughness, and damage-tolerant titanium alloy. Due to its excellent strength, plasticity, and fracture toughness, it has attracted more and more attention in the past decade [11,16]. Integrating a high-damage-tolerant TC4ELI titanium alloy with a high-strength TC21 titanium alloy can achieve a combination of strength and toughness on the same component, enabling the performance advantages of each material to be fully utilized and improving structural efficiency.…”

Effect of Third-Stage Heat Treatments on Microstructure and Properties of Dual-Phase Titanium Alloy

“…Wang [ 10 ] studied that TC21 titanium alloy is mainly composed of equiaxed grains and residual phases, and 880 °C is the appropriate annealing temperature for uniform microstructure refinement of hot-rolled TC21 titanium alloy. Hou [ 11 ] studied the effects of solution cooling rate and aging temperature on the structure of TC21 alloy. The results showed that the morphology of the primary α phase was mainly affected by the solid solution, and different cooling rates significantly affected the volume ratio of β phases and secondary α phases.…”

Effect of Cooling Rate and Aging Process on Wear Behavior of Deformed TC21 Ti-Alloy

“…Solution and aging treatments have been chosen to optimize microstructure and wear properties of TC21 Ti-alloy by changing solution temperatures and cooling rate after solution treatment [12]. Recently, a variety of studies investigated the effect of thermomechanical treatment [13], and oxidation treatment [14] on fatigue behavior [15] and fracture toughness of TC21 Ti-alloy [4]. However, detailed examination of the effect of solution treatment and aging processes on wear behavior is rarely reported.…”