Effect of Ti addition on the mechanical properties and microstructure of novel Al-rich low-density multi-principal-element alloys

In this work, the effect of Ti content on the microstructure and mechanical properties of low-density Fe30Mn-10Al-1.57C-2.3Cr-0.3Si-chi Ti (chi = 0, 0.3, 0.6, and 0.9 wt%) alloys was systematically investigated. The results reveal that hot deformation, followed by solid-solution treatment at 1050 degrees C (3 h) and thermal aging at 350 degrees C (6 h), ensures outstanding mechanical properties. The low-density alloys exhibit completely austenite microstructures with carbides. The original carbide phase, the so-called kappa-carbide, is observed in the low-density Ti-free specimen. However, increase in the Ti content leads to the reduction of this phase and the emergence of a new type of carbide, i.e., TiC. Moreover, the grain size of austenite phase is refined with Ti addition, resulting in a superior yield strength. In addition, the low-density alloy with a Ti concentration of 0.6 wt% demonstrates optimal mechanical properties with the yield strength of 1031.75 MPa, the ultimate tensile strength of 1158.55 MPa, and the total elongation of 23.96%. It is worth noting that the novel low-density alloy exhibits a density of 6.65 g/cm(3), which is similar to 14.74% lower than that of traditional steel (7.8 g/cm(3)) and can be ascribed to the incorporation of lightweight Al element. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The addition of Ti in low-density Fe30Mn-10Al-1.57C-2.3Cr-0.3Si alloys can optimize mechanical properties by reducing the original carbide phases and introducing TiC, refining the grain size of austenite phase, and achieving higher strength. Among the investigated alloys, the one with 0.6 wt% Ti concentration demonstrates the best mechanical properties, with a yield strength of 1031.75 MPa, an ultimate tensile strength of 1158.55 MPa, and a total elongation of 23.96%.