Title: The Elevated-Temperature Strength Enhancement of a Low-Cost β Titanium Alloy Through Thermomechanically-Induced Phase Transformation

Abstract

The effects of temperature and thermomechanical loading on the tensile strength and hardness were studied for a rolled, low-cost metastable β titanium alloy, Ti-13Cr-1Fe-3Al (wt.%). Tensile tests were performed at temperatures between room temperature (RT) and 410°C. The results indicated that the ultimate tensile strength (UTS) decreased with increasing temperatures up to 300°C. However, the UTS was 1400 MPa at 410°C, which was approximately 150% higher than the RT UTS. It is believed that the formation of nanoscale ω and α precipitates, identified using transmission electron microscopy, hindered the dislocation motion, which resulted in the exceptionally high UTS at 410°C. However, ductility was maintained, as the elongation-to-failure (ϵ_f) was 10% at 410°C. Dynamic mechanical analysis suggested that phase transformations occurred between 370°C-475°C. To evaluate the effect of the phase transformations on the hardness, the as-received material was heat treated at 400°C, 450°C, and 500°C for 2 h, which resulted in hardness values of approximately 340 Hv, 380 Hv, and 470 Hv, respectively. However, the greatest hardness value (500 Hv) was exhibited by the as-received material after it was tensile tested at 410°C. This suggested that both temperature and loading history affected the phase transformations. Finally, as all the samples exhibitedmore » a ductile fracture mode, this work indicates that it is possible to maintain both high strength and adequate ϵ_f for Ti-13Cr-1Fe-3Al (wt.%).« less

Authors:

Khademi, V. ^[1]; Ikeda, M. ^[2]; Hernández-Escobar, D. ^[1]; Boehlert, C. J.  ^[1]

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+ Show Author Affiliations

1. Michigan State Univ., East Lansing, MI (United States)
2. Kansai Univ., Suita (Japan)

Publication Date:

2019-06-19

Research Org.:

Michigan State Univ., East Lansing, MI (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division

OSTI Identifier:

1595235

Grant/Contract Number:  

SC0001525; FG02-09ER46637

Resource Type:

Accepted Manuscript

Journal Name:

JOM. Journal of the Minerals, Metals & Materials Society

Additional Journal Information:

Journal Volume: 71; Journal Issue: 10; Journal ID: ISSN 1047-4838

Publisher:

Springer

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE