Some Distinct Features of Transformative High Entropy Alloys for Metal Additive Manufacturing

Abstract

Sudden damage in engineering materials during service was always a challenge, and a lot of efforts have been put forward by materials scientists to resolve this issue. This motivated the design of a variety of classes of alloys such as stainless steel, deformed and partitioned steels, metastable Ti alloys, and recently developed high entropy alloys (HEA). A continuous evolving journey from single-phase to multi-phase HEAs showed exceptional work hardenability in them, which is required for improved failure resistance in metallic systems. In line with that, recently developed transformative high entropy alloys (T-HEAs) displayed interesting outcomes in terms of improved damage tolerance (σUTS ∼1.2 GPa and ductility ∼20% with 1.5% defect density) after conventional processing, severe deformation, and laser-assisted 3D printing. These outcomes were attributed to the localized WH activity within the stress concentration regions due to the activation of transformation induced plasticity (TRIP) effect near the defects. As a result, defects present in these T-HEAs act as sites for delaying the damage by showing a pronounced transformation induced crack retardation (TRICR) effect, thereby improving failure resistance during service.