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Microstructure and temperature dependence of the microhardness of W-4V-1La<inf>2</inf>O<inf>3</inf> and W-4Ti-1La<inf>2</inf>O<inf>3</inf>

Abstract:

W-4V-1La2O3 and W-4Ti-1La2O3 (wt.%) alloys have been produced by mechanical alloying and subsequent hot isostatic pressing. Electron microscopy observations revealed that these alloys exhibit a submicron grain structure with a dispersion of La oxide nanoparticles. Large V or Ti pools with martensitic characteristics are found segregated in the interstices between the W particles of the respective alloys. Microhardness tests were carried out over the temperature range 300-1073 K in vacuum. The microhardness-temperature curve for W-4V-1La2O3 exhibited the expected decreasing trend with increasing temperature although the microhardness stayed constant between ∼473 and 773 K. The W-4Ti-1La 2O3 presented quite different temperature dependence with an anomalous microhardness increase for temperatures above ∼473 K. © 2013 Elsevier B.V. All rights reserved.