Improvement in Ductility in Commercially Pure Titanium Alloys by Stress Relaxation at Room Temperature

Irena Eipert; Giribaskar Sivaswamy; Rahul Bhattacharya; Muhammad Amir; Paul Blackwell

doi:10.4028/www.scientific.net/KEM.611-612.92

Paper Titles

Novel Experimental Set-Up to Test Tubes Formability at Elevated Temperatures
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Influence of the Identification Procedure of the Yield Criterion on the Thickness Prediction of the Square Cup
p.70

Investigation of the Hot Deformation Behavior of an Al-Mg-Sc-Zr Alloy under Plane Strain Condition
p.76

Study on Instability and Forming Limit of Sheet Metal under Stretch-Bending
p.84

Improvement in Ductility in Commercially Pure Titanium Alloys by Stress Relaxation at Room Temperature
p.92

Studies on Ductile Damage and Flow Instabilities during Hot Deformation of a Multiphase γ-TiAl Alloy
p.99

A Generalized Damage Model Accounting for Instability and Ductile Fracture for Sheet Metals
p.106

Influence of Cooling Rate on Free Interstitial Concentration in Type 430 Ferritic Stainless Steel
p.111

Heat Treatments Analysis of Steel Using Coupled Phase Field and Finite Element Methods
p.117

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Improvement in Ductility in Commercially Pure Titanium Alloys by Stress Relaxation at Room Temperature

Abstract:

Present work focusses on the effect of stress relaxation on the tensile behaviour of two commercially pure titanium alloys of different strength levels (Grade 1 and Grade 4) subjected to tensile tests at room temperature. The stress relaxation tests were performed by interrupting the tensile tests at regular strain intervals of 5% in the plastic region of the tensile curve and compared to the monotonic tensile tests at different strain rates ranging from 10^-4 to 10^-1s^-1. To understand the effect of anisotropy, samples were taken along 0° and 90° to rolling direction (RD) for both the alloys. Improvement in ductility of different levels at all the strain rates was observed in both the alloys when stress relaxation steps were introduced as compared to monotonic tests. However there is not much change in the flow stress as well as in strain hardening behaviour of the alloys. The true stress-true strain curves of Grade 4 samples taken in 90° to RD exhibited discontinuous yielding phenomenon after the yield point, which is termed as a yield-point elongation (YPE). The improvement in ductility of the Cp-Ti alloys can be linked to recovery process occurring during the stress relaxation steps which resulted in the improvement in ductility after repeated interrupted tensile tests. The paper presents and summarise the results based on the stress relaxation for the two different alloys.