Effect of annealing treatment on microstructure and mechanical properties of hot isostatic pressing compacts fabricated using Ti–6Al–4V powder

Abstract

The effects of annealing temperature and annealing time on microstructure evolution and mechanical properties of Ti-6Al-4V titanium alloy prepared using powder hot isostatic pressing were investigated. The results showed that when annealing temperature was ,1173 K, the globularisation of primary a was observed, and the morphology of secondary a changed from acicular shapes to acicular and continuous lathy grains. Scanning electron microscopy fracture surface showed that the fracture mechanism changed from transcrystalline dimple type to a mixture of transcrystalline and intercrystalline dimple types with increasing annealing temperature. The tensile strength and elongation varied with the temperature in an opposite trend. However, they varied similarly with increasing annealing time. Microhardness was sensitive to the annealing time, resulting into a maximum microhardness of 396.95 HV at 1173 K for 3 h.

Additive manufacturing titanium components with isotropic or graded properties by hybrid electron beam melting/hot isostatic pressing powder processing

“…Contrary to the results presented here, previous studies of Ti-6Al-4V consolidated from powder HIP have observed a higher aspect ratio, lath morphology of the grains 28,35 . Subsequent heat treatments were found to an increase the measured fraction of equiaxed grains, proportional to treatment time and temperature 35 . The mostly equiaxed α grains observed in the HIP consolidated powder analysed in this paper (EBS-H) is thus more typical of heat-treated HIP consolidated powder.…”

Investigation and optimization of heat treatment process on tensile behaviour of Ti6Al4V alloy

“…The annealing treatment at 900 °C and 950 °C shows a larger area fraction of the α phase. At 1000 °C the primary α transformed into lamellar β due to increased temperature [21].…”

High Cycle Fatigue Behaviour of 316L Stainless Steel Produced via Selective Laser Melting Method and Post Processed by Hot Rotary Swaging

“…Liang et al [30] found that the structure after HIP featured a series of typical columnar γ grains that grew along the building direction. Qu et al [31] revealed that the ultimate tensile strength and yield strength of a Ti-6Al-4V alloy sample decreased with a higher annealing temperature during HIP. Topping et al [32] showed that, despite the grain growth during HIP, an ultrafine grain structure within an aluminum alloy was retained, which consequently increased strength compared to the cast alloy.…”