Laser additive manufacturing of high-performance tungsten alloy by controlling thermal input

Tungsten (W), owing to its exceptional physical and chemical properties, is a promising candidate for plasma-facing materials. However, its intrinsic brittleness makes it highly susceptible to cracking during its processing, especially using the laser powder bed fusion (LPBF) process with high energy input. Alloying has been recognized as an effective strategy to deal with this challenge, yet investigations into rare earth element alloying for tungsten and corresponding LPBF production remain limited. In this study, yttrium (Y), a rare earth element, was introduced to alloy with tungsten, and W-Y alloys were fabricated via LPBF at various laser energy densities. Finite element simulations were conducted to predict the temperature field distributions of W-Y alloy under different laser energy densities, providing insight into the formation of metallurgical defects at various laser energy inputs. It revealed that at a suitable laser energy density of 500 J/mm3, the fabricated W-Y specimens exhibited smooth and flat melt paths without discernible internal pores or cracks, achieving densification of 99.3%. The W-Y alloy had a refined microstructure with fine columnar and equiaxial grains, with an average grain size of 15.83 μm. The compressive strength and elongation after fracture of the W-Y alloy were 1531.93 MPa and 21.57%, respectively. The excellent hardness of 520 HV0.2 and wear resistance with a coefficient of friction (COF) of 0.47 were obtained. The enhanced mechanical performance could be attributed to grain refinement strengthening and dislocation strengthening. The study on the tensile properties of the intrinsic brittle W-Y sample was conducted for the first time, highlighting the intrinsic challenge of improving the tensile ductility of tungsten. This study not only provides a new perspective on rare-earth-alloyed tungsten but also offers a scientific reference for LPBF processing of high-performance W-Y alloy.