Boosting Mechanical Properties of W6Mo5Cr4V2 Alloy Fabricated by Directed Energy Deposition Through Tempering Heat Treatment

Abstract

The utilization of laser‐directed energy deposition (DED) for fabricating alloys offers the potential to customize their mechanical and physical properties, surpassing traditional casting limitations. Herein, a DED‐adopted flat‐top laser is applied in producing W6Mo5Cr4V2 alloy, a material widely used in mold making, double‐screw production, and crushing roller manufacturing. To minimize its residual stress and potential defects, and enhance the performance of the deposited sample, it undergoes tempering heat treatment at 560 °C for 1 h. According to the analysis results, the deposited W6Mo5Cr4V2 alloy is predominantly composed of martensite, carbide, and a minor amount of retained austenite. Upon tempering, the retained austenite transforms into martensite, effectively reinforcing the properties of the W6Mo5Cr4V2 alloy by precipitating secondary carbides. Furthermore, the microhardness value of the alloy increases by 12% after tempering heat treatment. Both adhesive and abrasive wear are observed during the friction and wear process, resulting in a 10% reduction in friction coefficient, thereby significantly improving the wear resistance of the W6Mo5Cr4V2 alloy. The average tensile strength of the heat‐treated W6Mo5Cr4V2 sample is 762.34 MPa, which is higher than the deposited sample's 646.6 MPa. Notably, the tensile fracture displays typical brittle characteristics.