Zhongji Sun

Abstract Grain boundary hardening and precipitation hardening are important mechanisms for enhancing the strength of metals. Here, we show that these two effects can be amplified simultaneously in nanocrystalline compositionally complex alloys (CCAs), leading to near-theoretical strength and large deformability. We develop a model nanograined (TiZrNbHf)98Ni2 alloy via thermodynamic design.

1 Introduction Metal additive manufacturing (AM) provides one-step material synthesis, heat treatment, and shaping of ready-to-use parts for direct industrial deployment.[1] Components with ultrahigh hardness in their as-built state are critical, for instance, in precision instrument, molding, and drilling applications.

Abstract The far-from-equilibrium solidification during additive manufacturing often creates large residual stresses that induce solid-state cracking. Here we present a strategy to suppress solid-state cracking in an additively manufactured AlCrFe2Ni2 high-entropy alloy via engineering phase transformation pathway. We investigate the solidification microstructures formed during laser powder-bed fusion and directed energy deposition, encompassing a broad range of cooling rates.