Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:734

Article

Cramer, Jeff¹  Adams, Derrik²  Miles, Michael P.¹  Fullwood, David T.²  Homer, Eric R.²  Brown, Tyson³  Mishra, Raj K.³  Sachdev, Anil³ 

[1] Brigham Young Univ, Mfg Engn Technol, Provo, UT 84602 USA

[2] Brigham Young Univ, Mech Engn, Provo, UT 84602 USA

[3] Gen Motors R&D, Warren, MI USA

关键词: Q&P steel;    Strain path;    Retained austenite;    Forming limit;   

DOI  :  10.1016/j.msea.2018.07.062

来源: Elsevier

【 摘 要 】

Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension.

【 授权许可】

Free