Abstract Tungsten is generally too brittle to serve a robust structural function. Here, we explore the fracture toughness of 90–97 wt%W Ni-Fe liquid phase sintered tungsten heavy alloys (WHAs). The room temperature (RT) maximum load fracture toughness (KJm ≈ 69–107 MPa√m) of the WHA, containing only 3–10 wt% of a Ni–Fe ductile phase (DP), is ≈ 9–13 times higher than KIc typical of monolithic W (≈ 8 MPa√m). All the WHAs show extensive stable crack growth, and increasing blunting line toughness averaging ≈ 170 MPa√m, prior to significant crack extension. In contrast to classical ductile phase toughening, that is primarily due to macrocrack bridging, the WHA toughness increase mainly involves new mechanisms associated with arrest, blunting and bridging of numerous dilatational shielding process zone microcracks in the macrocrack process zone. Tests down to –196 °C, to partially emulate irradiation hardening, show decreasing toughness and a transition to elastic fracture at a temperature of –150 °C for 90W to –25 °C for 97W. However, even at –196 °C, the leanest DP 97W WHA KIc is ≈ 3 times higher than that of monolithic W at RT. Possible effects of the small specimen size used in this study are briefly summarized.

中文翻译：

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90 至 97W-NiFe 合金显着的断裂韧性揭示了强大的新型韧性相增韧机制

摘要 钨通常太脆，无法发挥强大的结构功能。在这里，我们探索了 90-97 wt% W Ni-Fe 液相烧结钨重合金 (WHA) 的断裂韧性。WHA 的室温 (RT) 最大载荷断裂韧性 (KJm ≈ 69-107 MPa√m)，仅含有 3-10 wt% 的 Ni-Fe 延性相 (DP)，比 DP 高 ≈ 9-13 倍单片 W 的典型 KIc (≈ 8 MPa√m)。在显着裂纹扩展之前，所有 WHA 都显示出广泛的稳定裂纹扩展，并增加了平均约 170 MPa√m 的钝线韧性。与主要由宏观裂纹桥接引起的经典韧性相增韧相反，WHA 韧性的增加主要涉及与宏观裂纹过程区中众多扩张屏蔽过程区微裂纹的阻滞、钝化和桥接相关的新机制。低至 –196 °C 的测试以部分模拟辐照硬化，表明在 –150 °C（90W）至 –25 °C（97W）的温度下韧性下降并转变为弹性断裂。然而，即使在 –196 °C 时，最贫乏的 DP 97W WHA KIc 也比单片 W 在室温下高 ≈ 3 倍。简要总结了本研究中使用的小样本的可能影响。