Square L1₂ precipitates inducing high susceptibility to adiabatic shear in 3D printed fine-grained tungsten heavy alloy with high-entropy alloy matrix

Tungsten heavy alloys with a L1₂ precipitation-hardening high-entropy alloy matrix exhibit high susceptibility to adiabatic shear, but the relationship between the size and morphology of L1₂ precipitates and the adiabatic shear behavior is not well understood. This work systematically studies the effect of different size and morphology L1₂ precipitates on the mechanical properties and susceptibility to adiabatic shear of the tungsten heavy alloy with an AlCrFeNiV-system high-entropy alloy matrix (W-HEA). The results show that the W-HEA with square L1₂ precipitates has tensile strength of 1300 MPa and dynamic compression strength of 2100 MPa at a stain rate of 6000 s⁻¹. The higher interfacial energy of square L1₂ precipitates leads to the faster re-dissolution of square L1₂ precipitates into the matrix than ultrafine and lath-like L1₂ precipitates under temperature rise during shearing, which can sharply soften the shearing location and contribute to the narrowest adiabatic shear band (ASB) with width of 15 μm.