Computational design of ultra-high thermal conductivity, crack-free aluminum alloys for additive manufacturing

To design ultra-high thermal conductivity (TC) aluminum alloys adapted to laser powder bed fusion, a multi-property optimization framework named HTCM has been introduced, integrating high-throughput CALPHAD and a multi-objective genetic algorithm to achieve both ultra-high TC and crack resistance. The framework prioritises TC while tailoring key metallurgical factors that govern grain refinement and eutectic solidification. Guided by HTCM, a novel Al-2.12Ni-0.41Zr-0.22Sc (HCA_1) alloy has been developed, exhibiting a crack-free microstructure. After peak aging at 375 °C/7 h, HCA_1 achieves a TC of 201–207 W/(m·K) and an ultimate tensile strength (UTS) of 323–330 MPa, ranking among top-tier counterparts. Microstructural analysis validates the HTCM design strategy: the as-built microstructure features a bimodal grain structure nucleated on primary L12-Al3(Sc,Zr) particles and nanoscale eutectic Al-Al3Ni networks. Aging produces a high density of nanoscale Al3Ni and coherent L12-Al3(Sc,Zr) precipitates, synergistically enhance strength and TC. The HTCM's transferability is further demonstrated by designing an Al-1.33Fe-0.34Zr (HCA_2) alloy, which achieves an unprecedented TC of 215 W/(m·K) and a UTS of 262 MPa after peak aging at 400 °C/4 h. Compared to conventional trial-and-error approaches, HTCM significantly shortens the alloy design cycle, providing a new pathway for accelerating the development of high-performance materials for specific applications.