| Summary: | The hot compression bonding (HCB) in a Fe–9Cr-1.5W-0.3Ti alloy, under three conditions: (i) coarse-grained; (ii) fine-grained hot isostatic pressed (HIP); and (iii) fine-grained nano-oxide dispersion strengthened (ODS), was performed at 800 °C with strains of 10% and 30% and followed by soaking treatment at 1000 °C for 4 h. The effects of grain size and nano-oxide particles on the interfacial microstructure evolution and healing mechanism were systematically investigated. The results showed that grain boundary bulging and small recrystallized grains formed along the straight bonding interface of the coarse-grained alloy were related to discontinuous dynamic recrystallization behavior. In contrast, a layer of fine recrystallized grains was located at the bonding interface of the fine-grained HIP alloy, which was a typical rotation dynamic recrystallization behavior. Although the interfacial recrystallization behavior of the fine-grained ODS alloy was also rotation dynamic recrystallization, nano-oxide particles inhibited interfacial recrystallization and oxide transformation. Based on the interfacial bonding ratio considering different features of HCB, the ranking of interface bonding ability was coarse-grained alloy < ODS alloy < HIP alloy.
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