Superplastic deformation of Co{sub 3}Ti alloy

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(97)00217-0· OSTI ID:541017

Kim, W Y; Hanada, S; Takasugi, T ^[1]

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1. Tohoku Univ., Sendai (Japan). Inst. for Materials Research

The high temperature deformation of Co{sub 3}Ti alloy consisting of L1{sub 2} single phase was observed at temperatures of 1,173 K to 1,273 K and at initial strain rates of 3.2 {times} 10{sup {minus}5} to 7.9 {times} 10{sup {minus}4} s{sup {minus}1}. The obtained results were summarized as follows. The high temperature flow behavior of Co{sub 3}Ti alloy was divided into two regions. In the region of higher strain rate (also at lower temperature and large grain size), the stress vs. strain curves exhibited a stress peak followed by a rapid work softening while in the region of lower strain rate (also higher temperature and small grain size), the stress vs. strain curves exhibited a gradual work hardening followed by a steady state flow. The dynamic recrystallization (DRX) occurred in the higher strain rate (or the lower temperature) region while the grain coarsening occurred in the lower strain rate (or the higher temperature) region. The large tensile elongation, i.e. superplastic deformation occurred in the latter region. The high temperature deformation of Co{sub 3}Ti alloy characterized by the constitutive equation was divided into two regions; in the higher strain rate (or the lower temperature) region, n = 2.7 and Q = 154 kJ/mol were estimated while in the lower strain rate (or the higher temperature) region, n = 1.7 and Q = 80 kJ/mol were estimated. Based on mechanical behavior and microstructural observation, it is suggested that the grain boundary sliding-based mechanism is responsible for the superplastic deformation of Co{sub 3}Ti alloy observed in this work.

• OSTI ID: 541017
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 7 Vol. 37; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT ALLOYS
GRAIN BOUNDARIES
GRAIN SIZE
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
PLASTICITY
RECRYSTALLIZATION
SAMPLE PREPARATION
STRAIN RATE
STRAINS
STRESSES
TEMPERATURE RANGE 1000-4000 K
TITANIUM ALLOYS