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Abstract The performance of tungsten heavy alloys (WHAs) is related to the characteristic of matrix/W interfaces, which depends directly on the wettability of the matrix materials on W. This work designs a novel WHA that selects an AlCrFeNiV-system high entropy alloy (HEA) as matrix based on its wetting behavior on polycrystalline W. The wetting experiments show that this W/HEA system exhibits low contact angles at the temperatures for liquid phase sintering (LPS), and dissolutive wetting with a moderate W solubility in the HEA. This favorable wetting behavior benefits the densification process during LPS, leading to clean matrix/W interfaces with high bonding strength and hence a high ultimate tensile strength of 1132 MPa in the resulting W/HEA composite. These results indicate that the AlCrFeNiV-system HEA is a promising matrix material for WHAs. Graphical abstract Image 1 Highlights • A novel tungsten heavy alloy using high entropy alloy as matrix (W/HEA composite) is prepared by liquid phase sintering. • Dissolutive wetting of W by HEA melt with low contact angles is investigated. • W/HEA composite has fine W particle size of 13.15 μm and strong interfacial bonding. • W/HEA composite has a high yield strength of 705 MPa and high ultimate tensile strength of 1132 MPa. [ABSTRACT FROM AUTHOR]

High density, high strength and high susceptibility to adiabatic shear banding (ASB) have always been pursued by tungsten heavy alloys (WHAs) for kinetic energy armor-piercing projectiles. To meet the demand, this work reported a novel tungsten heavy alloy with high-density L1 2 precipitation-strengthened Co9Al9W binder (WCAW). WCAWs were prepared by liquid phase sintering (LPS) and laser ultrashort-time liquid phase sintering (LULPS) respectively. Experimental results show that LULPS technique with large molten pool convection and rapid solidification can produce WCAWs with uniform W distribution, low W-W contiguity and fine W particles. Conversely, W particles in LPS WCAWs were excessively connected and segregated. The uniform distribution, low W-W contiguity and fine W particles enable LULPS WCAW to exhibit better mechanical properties. The ultimate compressive strength of the LULPS WCAWs is ∼2442 MPa, 16.4 % higher than that of the LPS WCAWs. As well, the dynamic yield strength of LULPS WCAWs is high, which is ∼2281 MPa and 37.4 % higher than that of LPS WCAWs. • A novel tungsten heavy alloy with Co9Al9W binder (WCAW) was developed. • WCAWs with high W content of 93 wt% were prepared by two different techniques (LPS and LULPS). • W particles in LULPS WCAWs were fine and distributed uniformly in γ matrix. • LULPS WCAWs showed much higher compressive strength and dynamic strength than LPS WCAWs. [ABSTRACT FROM AUTHOR]

Preparing bulk WNiFe alloys with high strengths and low W content (<80 wt%) is challenging. Here, we present a strategy, powder-fed laser melting deposition (LMD), to solve this problem. The LMD-prepared WNiFe (LMD WNiFe) samples show high mechanical strengths and low W contents of 50 and 75 wt%. The W particles in the LMD WNiFe samples uniformly distribute in the matrix (γ), exhibiting fine particle sizes of approximately one-fifth of those of conventional 93WNiFe alloys prepared by liquid phase sintering (LPS). The ultimate tensile strengths of the 50 and 75 wt% samples are 1120 and 1316 MPa, respectively, which are 24.44 and 59.33% higher than those of the LPS-prepared 93WNiFe alloy (LPS 93WNiFe). These results suggest a useful strategy for preparing low-W-content, high-strength WNiFe alloys with fine, uniformly distributed W particles. This finding offers new potential applications of WNiFe alloys in additive manufacturing. Unlabelled Image • WNiFe with W particle size of 5.5 μm is prepared by laser melting deposition (LMD). • WHAs with low W content (no W skeleton to keep shape) can be achieved by LMD. • W particles in LMD WHAs distribute uniformly in γ matrix. • The yield strength of LMD WHAs is 59.3% higher than that of LPS WHAs. [ABSTRACT FROM AUTHOR]

• Fine-grained tungsten heavy alloy (FG-WHA) is prepared by liquid phase sintering. • Novel matrix that reduces W grain growth rate brings about FG-WHA. • Fine W grain in WHA contributes to a high ultimate tensile strength of 1267 MPa. • The FG-WHA exhibit a nearly full density and a good elongation of 10%. It is difficult to prepare fine-grain tungsten heavy alloys (WHAs), e.g. W-NiFe, by liquid phase sintering (LPS) mainly because of high solubility of W in the NiFe matrix. To obtain fine W grains, this work proposes to reduce W grain growth rate by selecting a high entropy alloy (HEA) with low diffusivity and solubility of W as the matrix of WHA. The results show that the LPS W-HEA has a fine W grain size of ~9.7 μm, which is about a third of the value in the conventional LPS W-NiFe. The fine W grains in the as-sintering W-HEA contribute to high yield strength and ultimate tensile strength of 840.8 MPa and 1267.3 MPa, respectively. These results suggest a new pathway for obtaining a fine-grain WHA by tailoring the matrix composition. [ABSTRACT FROM AUTHOR]