Effect of HfC on microstructure and room temperature/high temperature properties of Mo La2O3 Alloys

DOI:	10.11809/bqzbgcxb2025.01.038
Keywords:	powder metallurgy; molybdenum alloy; HfC; microstructure; mechanical property
Abstract:	Mo La2O3/HfC alloys were prepared via a powder metallurgy method in this paper. The phase distribution, microstructure and fracture morphology of Mo La2O3/HfC alloys were studied. The room temperature/high temperature mechanical properties and high temperature oxidation resistance of alloys were tested. The results indicate that the microneously doped HfC particles and La2O3 particles are dispersed and distributed in the molybdenum matrix. The grain size of molybdenum decreases as the mass fraction of HfC increases. The fibrous tissue of mechanically interspersed and overlapped with each other shows a trend of gradually getting shorter and thinner. It is proved that longitudinal fracture is intergranular brittle fracture. The cross sectional fracture is dimple fracture and cleavage fracture. The toughness along axial direction is better than that along the radial direction. The room temperature/high temperature strengths, flexural strengths and flexural angles of the alloys increases first and then decreases with the increase of HfC content, and Mo(La2O3)1.5(HfC)2.0 alloys have the best mechanical properties.The mass loss rate of Mo(La2O3)1.5(HfC)2.0 alloys are significantly lower than that of Mo(La2O3)0.5 alloy, and the mass loss rate is only 0.87% when the oxidation time is 150 s. It is only 1/2 of the mass loss rate of Mo(La2O3)0.5 alloy.
Issue:	Vol. 46 No. 1 (2025)
Published:	2025-01-31
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