Different Mechanisms of ε-M and α′-M Variant Selection and the Influencing Factors of ε-M Reversion During Dynamic Tension in TRIP Steel

Abstract

The variant selection of martensites (ε-M and α′-M) and ε-M reversion in dynamic tensile high-manganese TRIP steel were investigated. α′-M variant pairs with a zigzag morphology frequently formed, and the pairs of neighboring α′-M variants were examined in terms of mechanical work and strain energy reduction. The occurrence of a primary α′-M variant is determined by mechanical work, but high products of mechanical work and strain energy reduction are essential for secondary variant selection. In contrast to α′-M variant pair selection, ε-M variant selection can be attributed to the highest mechanical work. During ε-M→α′-M transformation, the mechanical work of ε-M reversion is higher than that of α′-M variant, thereby implying that ε-M reversion in 〈110〉 _γ grain is possible. ε-M plate distribution also affects the feasibility of ε-M reversion.