An Experimental Study of TRIP Behavior in a Cr-Ni-Mo-Al-Ti Maraging Steel

Quantitative Identification of Backstress Evolution and Iso-Volume Fraction Lines

Abstract

The quantitative identification of the backstress evolution is carried out in a Cr-Ni-Mo-Al-Ti maraging steel under thermomechanical loading conditions. The evolution depends on the direction of the applied stress; tensile, compressive or shear. The iso-volume fraction lines (the iso-ξ lines) are determined between the transformation-start line and the transformation-finish line on the applied hold stress-temperature plane. The iso-ξ lines are composed of a tensile-branch and a compressive-branch, each of which is parallel to the martensite-start line. The cross point of the tensile- and compressive-branches of the iso-ξ line shifts to the direction of the backstress evolution. The almost hold stress-independent martensite-finish line is proved to be attributed to the backstress evolution.