Anisotropy of Young's modulus and tensile properties in cold rolled α′ martensite Ti-V-Sn alloys

Hiroaki Matsumoto, Akihiko Chiba, Shuji Hanada

研究成果: Article査読

18 被引用数 (Scopus)

抄録

Young's modulus and tensile properties of cold rolled Ti-8 mass% V and (Ti-8 mass% V)-4 mass% Sn alloy plates consisting of α′ martensite were investigated as a function of tensile axis orientation in this work. A single phase of α′ (hcp) martensite is obtained in Ti-8 mass% V and (Ti-8 mass% V)-4 mass% Sn alloys by quenching after solution treatment. By 86% cold rolling, acicular α′ martensite microstructures change into extremely refined dislocation cell-like structure with an average size of 60 nm, accompanied with the development of cold rolling texture in which the basal plane normal is tilted from the plate normal direction (ND) toward transverse direction (TD) at angles of ±49° for Ti-8% V alloy and ±46° for (Ti-8 mass% V)-4 mass% Sn alloy. No apparent anisotropy of Young's modulus (E) is observed for as-quenched Ti-8% V (E = 76-83 GPa) and (Ti-8% V)-4%Sn (E = 69-79 GPa). In contrast, Young's modulus increases with increasing angle from the rolling direction (RD) to TD for cold rolled Ti-8% V (E = 72-94 GPa) and (Ti-8% V)-4%Sn (E = 63-85 GPa). The observed anisotropy of Young's modulus can be reasonably explained in terms of the cold rolling α′ texture. 0.2% proof stress and tensile strength are independent of tensile orientation for cold rolled Ti-8% V and (Ti-8% V)-4%Sn alloys. In contrast, larger elongation to fracture is obtained in specimens deviated by 30°, 45° and 60° from RD than by 0°, 75° and 90°. Scanning electron microscopy (SEM) fractographs reveal that quasi-cleavage-like fracture plane appears in 0° specimen of cold rolled Ti-8% V which shows brittle fracture and other specimens of cold rolled Ti-8% V and (Ti-8% V)-4%Sn alloys are fractured accompanied with necking and dimple formation. It is suggested from these results that brittle fracture is related to the activation of limited number of slip system and Sn addition leads to the activation of multiple slip systems.

本文言語English
ページ(範囲)503-510
ページ数8
ジャーナルMaterials Science and Engineering A
486
1-2
DOI
出版ステータスPublished - 2008 7 15

ASJC Scopus subject areas

  • 材料科学(全般)
  • 凝縮系物理学
  • 材料力学
  • 機械工学

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