Effect of process parameters on microstructure and properties of W-Ti-Zr-Nb tungsten alloy fabricated by LPBF

A novel tungsten alloy with the composition 73W-9Ti-9Zr-9Nb was successfully fabricated by Laser Powder Bed Fusion (LPBF). This study investigates the relationship between process parameters and the microstructure, defects, phases and mechanical properties of the alloy. The results revealed that with an increase in the laser power (P) from 50 to 100 W, the number of unmelted W particles decreased, transitioning the microstructure of the as-fabricated samples from W particles embedded in the Ti-Zr-Nb matrix to W dendrites within the Ti-Zr-NbW matrix. Simultaneously, the porosity decreased from 20.1 % to 0.1 % as the P increased. There was no W2Zr brittle phase in W-Ti-Zr-Nb, and the interface between the W particles, W dendrites, and the matrix was well- bonded. the interfaces between the W particles, W dendrites, and the matrix were well-bonded. As a result of these optimized processing conditions, the sample processed at a P of 100 W exhibited optimal overall performance, achieving a microhardness of 612.8 HV and an ultimate compressive strength of 2410 MPa. Increasing the laser power improved the overall performance of the material by reducing defects, increasing the proportion of dendrites, and enhancing solution strengthening.