Twinning-induced plasticity (TWIP) and work hardening in Ti-based metallic glass matrix composites

Abstract

The present study demonstrates that Ti-based metallic glass matrix composites (MGMCs) with a normal composition of Ti43Zr32Ni6Ta5Be14 containing ductile dendrites dispersed in the glass matrix has been developed, and deformation mechanisms about the tensile property have been investigated by focusing on twinning-induced plasticity (TWIP) effect. The Ti-based MGMC has excellent tensile properties and pronounced tensile work-hardening capacity, with a yield strength of 1100 MPa and homogeneous elongation of 4%. The distinguished strain hardening is ascribed to the formation of deformation twinning within the dendrites. Twinning generated in the dendrites works as an obstacle for the rapid propagation of shear bands, and then, the localized necking is avoided, which ensures the ductility of such kinds of composites. Besides, a finite-element model (FEM) has been established to explain the TWIP effect which brings out a work-hardening behavior in the present MGMC instead of a localized strain concentration. According to the plasticity theory of traditional crystal materials and some new alloys, TWIP effect is mainly controlled by stacking fault energy (SFE), which has been analyzed intensively in the present MGMC.

Exceptionally shear-stable and ultra-strong Ir-Ni-Ta high-temperature metallic glasses at micro/nano scales

“…As a result, MGs display a propensity for catastrophic and instantaneous brittle failure [12], which has become the Achilles' heel for their structural applications. Over the past decades, significant efforts have improved the deformability of MGs, mostly focusing on uniformly distributing shear bands via introducing secondary phases or structural inhomogeneities into glassy matrix or hindering the propagation of a single shear band [13][14][15][16][17][18]. In this sense, the stability of shear banding or shear stability of MGs are essential for the enhanced deformability of MGs.…”

Numerical Modeling and Simulations of Twinning-Induced Plasticity Using Crystal Plasticity Finite Element Method

“…Twinning-induced plasticity (TWIP) steels have broad range of applications due to their promising combination of work hardening, formability, and tensile strength [6][7][8]. These characteristics make it a dominant candidate for many advanced material applications.…”

“…Since twin regions behave as obstacles in dislocation glide, the dislocation mean free path may reduce. This eventually improves the strain hardening of TWIP steels [7,13,14]. Furthermore, in Fe-Mn-C grade, twin regions normally comprise a huge magnitude of sessile dislocations' density.…”

“…It can be stated that the excellent combination of strength and ductility in TWIP steels is primarily due to work hardening, which may be induced in a material due to the twinning mechanism. The secondary mode of plastic deformation, mechanical twinning, may occur in metals (in conjunction with slip), non-metals, and metallic glasses [6,7,17]. However, the fraction of twinning is highly dependent on the chemical composition of the alloy, as well as the physical conditions [18][19][20][21].…”