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Effect of heat treatment at the temperature above β‐transus on the microstructures and fatigue properties of pure Ti
Author(s) -
Uematsu Yoshihiko,
Huang Ching An,
Kakiuchi Toshifumi,
Mizutani Yoshiki,
Nakajima Masaki
Publication year - 2020
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/ffe.13292
Subject(s) - materials science , martensite , quenching (fluorescence) , dwell time , microstructure , diffusionless transformation , metallurgy , fatigue limit , composite material , fatigue testing , medicine , clinical psychology , physics , quantum mechanics , fluorescence
Commercially pure Ti (CP‐Ti) was heat treated at 1273 K (1000°C), which was higher than β‐transus temperature, followed by water quenching. The dwell time at 1000°C was changed from 1 to 240 h. The heat treatment at 1000°C resulted in α grain coarsening, whereas martensitic transformation occurred due to the rapid cooling from β phase. The hardness increased by the martensitic transformation, where higher hardness was achieved by longer dwell time at 1000°C. However, the fatigue strengths of the heat‐treated CP‐Ti were lower than that of the as‐received one. The fatigue strength of the specimen with the shortest dwell time of 1 h was the lowest among the heat‐treated samples with different dwell times. Untransformed coarse α grains were seen in the heat‐treated specimens, which resulted in the lower fatigue crack initiation resistance and fatigue strength than the as‐received specimen.