The hot forging behaviour and its effects on the oxidation behaviour of W–Cr alloy

• Hot forging on W–20Cr–20Mo–1.5Pd alloy was carried out.
• Residual pores were eliminated at suitable condition.
• Grain boundaries were rich in both Cr and Pd after hot forging.
• Enhanced oxidation resistance after hot forging due to Pd-and Cr-rich grain boundary and fewer residual pores.

For the first time, hot compression of a sintered W–20Cr–20Mo–1.5Pd alloy was performed to improve oxidation resistance. Residual pores in as-sintered alloy were hypothesized to be eliminated through sliding of the viscous Pd–Cr-containing grain boundary during compression at 10−4 s−1 and 1350 °C, which increased the alloy’s oxidation resistance. Because of sufficient Cr from the Pd–Cr phase near the grain boundary after hot compression, Cr could transfer more efficiently into the Cr-depleted zone, and therefore, the oxide film/matrix interface was much stronger and showed fewer interfacial cracks than the as-sintered alloy did.

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