Moderating strain hardening rate to produce high ductility and high strength in a medium carbon TRIP steel

Abstract

High strain hardening rate is usually pursued for high ductility. Here we report that moderate strain hardening rate is desired for producing better ductility and high yield strength, which is demonstrated in a medium carbon TRIP steel. By adjusting the temperature for bainitic transformation, the morphology, carbon content and residue stress of retained austenite were tuned to tailor the TRIP kinetics during tensile tests, which produced moderated but long-lasting strain hardening for high ductility while at the same time resulted in high yield strength. This strategy should work well for most materials, which usually have a limited ultimate strength.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

A principle is proposed and verified that an optimized moderate strain hardening rate is desired to produce the best mechanical properties for metallic materials.

KEYWORDS:

• TRIP
• mechanical properties
• strain hardening rate
• ductility
• strength

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is supported by the Natural Science Foundation of China (NSFC) (No. 51574079), the Fundamental Research Funds for the Central Universities (No. N2002013), and the Hong Kong Research Grants Council (GRF 11214121).