Solid solution hardening and precipitation hardening of α2-Ti3Al in Ti-Al-Nb alloys

Kei Shimagami, Sae Matsunaga, Atsushi Yumoto, Tsutomu Ito, Yoko Yamabe-Mitarai

Research output: Contribution to journalArticle

Abstract

Microstructure and mechanical properties of Ti-Al-Nb-based alloys were investigated as they are important in the development of new generation high temperature Ti alloys due to good oxidation resistance. The alloy compositions Ti-15Al-2Nb (to obtain α2 precipitates) and Ti-15Al-2Nb-0.5Si (at%) (to obtain solid-solution hardening by Si) were selected. Heat treatment at 1000°C after forging and rolling at 900°C transformed the β phase to α phase and α′ martensite during cooling. By heat treatment at 900°C, a single α phase was obtained in both alloys. The α2 phase was formed by aging treatment at 600 and 700°C of Ti-15Al-2Nb and at 600, 700, and 800°C of Ti-15Al-2Nb-0.5Si. Compressive strength was investigated for samples heat treated at 900°C with a single α phase and those aged at 600, 700, 800°C with α2 precipitates. The solid solution hardening effect of Si was found at all test temperatures. Precipitation hardening effect by α2 precipitates was also observed in both alloys and the effect improved with Si addition. Peaks of precipitation hardening were obtained at 300°C in both alloys; the precipitation hardening effect decreased with increase of test temperature above 300°C. It is suggested that a shearing mechanism occurs up to 300°C, which changes to a bypass mechanism above 450°C.

LanguageEnglish
Pages1404-1410
Number of pages7
JournalMaterials Transactions
Volume58
Issue number10
DOIs
StatePublished - 2017

Fingerprint

precipitation hardening
Age hardening
hardening
Hardening
Solid solutions
solid solutions
Precipitates
precipitates
heat treatment
Heat treatment
forging
oxidation resistance
bypasses
compressive strength
Oxidation resistance
heat resistant alloys
Forging
martensite
Superalloys
shearing

Keywords

  • Compressive strength
  • Precipitation hardening
  • Solid solution hardening
  • Titanium alloy
  • α phase
  • α-TiAl

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Solid solution hardening and precipitation hardening of α2-Ti3Al in Ti-Al-Nb alloys. / Shimagami, Kei; Matsunaga, Sae; Yumoto, Atsushi; Ito, Tsutomu; Yamabe-Mitarai, Yoko.

In: Materials Transactions, Vol. 58, No. 10, 2017, p. 1404-1410.

Research output: Contribution to journalArticle

Shimagami, K, Matsunaga, S, Yumoto, A, Ito, T & Yamabe-Mitarai, Y 2017, 'Solid solution hardening and precipitation hardening of α2-Ti3Al in Ti-Al-Nb alloys' Materials Transactions, vol. 58, no. 10, pp. 1404-1410. DOI: 10.2320/matertrans.MAW201707
Shimagami K, Matsunaga S, Yumoto A, Ito T, Yamabe-Mitarai Y. Solid solution hardening and precipitation hardening of α2-Ti3Al in Ti-Al-Nb alloys. Materials Transactions. 2017;58(10):1404-1410. Available from, DOI: 10.2320/matertrans.MAW201707
Shimagami, Kei ; Matsunaga, Sae ; Yumoto, Atsushi ; Ito, Tsutomu ; Yamabe-Mitarai, Yoko. / Solid solution hardening and precipitation hardening of α2-Ti3Al in Ti-Al-Nb alloys. In: Materials Transactions. 2017 ; Vol. 58, No. 10. pp. 1404-1410
@article{085afffa17a747a285f558139da7487a,
title = "Solid solution hardening and precipitation hardening of α2-Ti3Al in Ti-Al-Nb alloys",
abstract = "Microstructure and mechanical properties of Ti-Al-Nb-based alloys were investigated as they are important in the development of new generation high temperature Ti alloys due to good oxidation resistance. The alloy compositions Ti-15Al-2Nb (to obtain α2 precipitates) and Ti-15Al-2Nb-0.5Si (at{\%}) (to obtain solid-solution hardening by Si) were selected. Heat treatment at 1000°C after forging and rolling at 900°C transformed the β phase to α phase and α′ martensite during cooling. By heat treatment at 900°C, a single α phase was obtained in both alloys. The α2 phase was formed by aging treatment at 600 and 700°C of Ti-15Al-2Nb and at 600, 700, and 800°C of Ti-15Al-2Nb-0.5Si. Compressive strength was investigated for samples heat treated at 900°C with a single α phase and those aged at 600, 700, 800°C with α2 precipitates. The solid solution hardening effect of Si was found at all test temperatures. Precipitation hardening effect by α2 precipitates was also observed in both alloys and the effect improved with Si addition. Peaks of precipitation hardening were obtained at 300°C in both alloys; the precipitation hardening effect decreased with increase of test temperature above 300°C. It is suggested that a shearing mechanism occurs up to 300°C, which changes to a bypass mechanism above 450°C.",
keywords = "Compressive strength, Precipitation hardening, Solid solution hardening, Titanium alloy, α phase, α-TiAl",
author = "Kei Shimagami and Sae Matsunaga and Atsushi Yumoto and Tsutomu Ito and Yoko Yamabe-Mitarai",
year = "2017",
doi = "10.2320/matertrans.MAW201707",
language = "English",
volume = "58",
pages = "1404--1410",
journal = "Materials Transactions",
issn = "1345-9678",
publisher = "Japan Institute of Metals (JIM)",
number = "10",

}

TY - JOUR

T1 - Solid solution hardening and precipitation hardening of α2-Ti3Al in Ti-Al-Nb alloys

AU - Shimagami,Kei

AU - Matsunaga,Sae

AU - Yumoto,Atsushi

AU - Ito,Tsutomu

AU - Yamabe-Mitarai,Yoko

PY - 2017

Y1 - 2017

N2 - Microstructure and mechanical properties of Ti-Al-Nb-based alloys were investigated as they are important in the development of new generation high temperature Ti alloys due to good oxidation resistance. The alloy compositions Ti-15Al-2Nb (to obtain α2 precipitates) and Ti-15Al-2Nb-0.5Si (at%) (to obtain solid-solution hardening by Si) were selected. Heat treatment at 1000°C after forging and rolling at 900°C transformed the β phase to α phase and α′ martensite during cooling. By heat treatment at 900°C, a single α phase was obtained in both alloys. The α2 phase was formed by aging treatment at 600 and 700°C of Ti-15Al-2Nb and at 600, 700, and 800°C of Ti-15Al-2Nb-0.5Si. Compressive strength was investigated for samples heat treated at 900°C with a single α phase and those aged at 600, 700, 800°C with α2 precipitates. The solid solution hardening effect of Si was found at all test temperatures. Precipitation hardening effect by α2 precipitates was also observed in both alloys and the effect improved with Si addition. Peaks of precipitation hardening were obtained at 300°C in both alloys; the precipitation hardening effect decreased with increase of test temperature above 300°C. It is suggested that a shearing mechanism occurs up to 300°C, which changes to a bypass mechanism above 450°C.

AB - Microstructure and mechanical properties of Ti-Al-Nb-based alloys were investigated as they are important in the development of new generation high temperature Ti alloys due to good oxidation resistance. The alloy compositions Ti-15Al-2Nb (to obtain α2 precipitates) and Ti-15Al-2Nb-0.5Si (at%) (to obtain solid-solution hardening by Si) were selected. Heat treatment at 1000°C after forging and rolling at 900°C transformed the β phase to α phase and α′ martensite during cooling. By heat treatment at 900°C, a single α phase was obtained in both alloys. The α2 phase was formed by aging treatment at 600 and 700°C of Ti-15Al-2Nb and at 600, 700, and 800°C of Ti-15Al-2Nb-0.5Si. Compressive strength was investigated for samples heat treated at 900°C with a single α phase and those aged at 600, 700, 800°C with α2 precipitates. The solid solution hardening effect of Si was found at all test temperatures. Precipitation hardening effect by α2 precipitates was also observed in both alloys and the effect improved with Si addition. Peaks of precipitation hardening were obtained at 300°C in both alloys; the precipitation hardening effect decreased with increase of test temperature above 300°C. It is suggested that a shearing mechanism occurs up to 300°C, which changes to a bypass mechanism above 450°C.

KW - Compressive strength

KW - Precipitation hardening

KW - Solid solution hardening

KW - Titanium alloy

KW - α phase

KW - α-TiAl

UR - http://www.scopus.com/inward/record.url?scp=85030128374&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85030128374&partnerID=8YFLogxK

U2 - 10.2320/matertrans.MAW201707

DO - 10.2320/matertrans.MAW201707

M3 - Article

VL - 58

SP - 1404

EP - 1410

JO - Materials Transactions

T2 - Materials Transactions

JF - Materials Transactions

SN - 1345-9678

IS - 10

ER -