Significantly Enhanced Strength-Ductility Synergy in Ti-Al-based Alloy at 800°C Subjected to Pulsed Magnetic Field Treatment (PMT)

Abstract

Ti-Al-based alloys have emerged as promising lightweight alternatives to nickel-based superalloys in aerospace, energy, and automotive applications. However, their limited room-temperature plasticity and insufficient high-temperature strength significantly constrain their broader utilization in aerospace components. Pulsed magnetic field treatment (PMT) is a green and efficient method to enhance the mechanical properties of solid-state alloys. This study systematically investigates the effects of PMT on the microstructural evolution and mechanical performance of as-cast Ti-Al-X (Cr, V, Zr) alloys at both ambient and elevated temperatures (800℃), under varying magnetic induction intensities (B). Mechanical properties were evaluated through tensile testing. Among the tested samples, the alloy treated at B = 3 T exhibited optimal performance, with room-temperature elongation increasing by10.7% to 3.1% and tensile strength improving by 23.3% to 379.7 MPa. At 800℃, the tensile strength and elongation reached 544.2 MPa and 14.3%, respectively, corresponding to enhancements of 4.9% and 32.4%. Fracture morphology analysis revealed a mixed fracture mode, featuring both inter-lamellar and trans-lamellar characteristics. The underlying mechanisms of PMT-induced microstructural and mechanical property improvements were elucidated, highlighting the roles of magnetic stress and thermal effects in refining lamellar spacing, reducing lamellar thickness, enhancing grain orientation, and promoting the precipitation of equiaxed γ-phase grains. Furthermore, the exceptional high-temperature performance was attributed to the synergistic effects of dislocation jog dragging (DJD) and twin-induced plasticity (TWIP) during deformation. These findings provide critical insights into the enhancement of TiAl alloy properties through advanced physical field treatments.