Revealing the solidification microstructure evolution and strengthening mechanisms of additive-manufactured W-FeCrCoNi alloy: Experiment and simulation

Tungsten heavy alloys (WHAs) prepared using laser additive manufacturing (AM) exhibit intricate geometries, albeit with limited mechanical properties. Here we designed a high-strength WHA featuring a FeCrCoNi high entropy alloy (HEA) binder via the laser metal deposition (LMD) technique. Due to the distinctive thermal cycle and rapid cooling rate, the as-deposited alloys exhibit microstructures with hypoeutectic, eutectic-like, and spot-like characteristics. To elucidate this phenomenon, the solidification paths were delineated and analyzed by combining microstructural characterization and phase equilibrium simulation. The mu phase precipitated out from the supersaturated solid solution, thereby nucleating massive dislocations on the FeCrCoNi matrix to increase the work hardening rate. Furthermore, the mu phase formed an ultrafine intermetallic compound (IMC) layer around the W grain, reducing the hole or crack between the W grain and FeCrCoNi matrix. Attributed to the precipitation strengthening, the solid solution of the FeCrCoNi binder, along with the load-bearing strength of W, the developed alloy achieved ultrahigh compressive stress and strain of 2047 MPa and 32 % respectively at room temperature. These findings contribute valuable insights to the advancement of additive manufacturing for tungsten alloys, leveraging their excellent properties. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.