Journal Published Online: 19 November 2019
Volume 8, Issue 1

Determination of Critical Conditions for Dynamic Recrystallization of Commercially Pure Titanium

CODEN: MPCACD

Abstract

Microstructural evolution and mechanical properties are controlled by dynamic recrystallization (DRX) during industrial processing. To identify the critical condition for initiation of DRX, hot isothermal compression tests of commercially pure (CP)-70 titanium were conducted in a temperature range of 750°C–1,100°C and strain rate range of 0.001–10 s−1 to a true strain of 0.69. The critical condition for initiation of DRX can be identified from the inflection point on the strain-hardening rate (θ=σ/ε) versus flow stress (σ) curve. A third-order polynomial equation was fitted to the experimental θσ data to find out the inflection point. The results show that the critical stress (σc) for the initiation of DRX can be expressed as σc=B/3A, where A and B are the coefficients of the third-order polynomial equation. It was observed that critical stress value depends on the deformation condition. The stress-strain curve was then normalized with respect to the peak stress (U=σ/σpvs.W=ε/εp), leading to a normalized value of critical stress, (Uc)=σc/σp=B/3A, where A′ and B′ are the coefficients of the normalized third-order equation. The value of Uc(0.95) is a constant and independent of deformation conditions. These parameters were then used to calculate the DRX fraction, and the relationship between DRX fraction and processing variables was established.

Author Information

Sonkar, Suresh
Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee, India
Pancholi, V.
Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee, India
Murty, S. V. S. N.
Materials and Metallurgy Group, Vikram Sarabhai Space Centre, Trivandrum, India
Pages: 15
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Details
Stock #: MPC20190050
ISSN: 2379-1365
DOI: 10.1520/MPC20190050