Preparation of High-Temperature Multicomponent Alloys by Mechanochemical Synthesis from Refractory Elements

摘要

Highly dispersed powders of two-phase multicomponent alloys have been prepared by mechanochemical synthesis from Hf0.5Nb0.5Ta0.5Ti1.5Zr1 (composition 1) and HfNbTaTiZrMo (composition 2) refractory-metal mixtures in a Fritsch (P-7) planetary mill under an Ar atmosphere. Two solid solutions, with BCC and HCP lattices, were obtained from the five-component mixture (composition 1). In the case of the six-component mixture (composition 2), both solid solutions had BCC lattices. Using compaction by hot isostatic pressing at a temperature of 1200 degrees C, we obtained dense samples. Mechanical tests in compression showed a combination of high strength and plasticity. For sample 1, we obtained a yield stress sigma(y) = 1317 MPa, compressive breaking stress sigma(b) = 1340 MPa, and relative breaking spread of 7%. Even better results were obtained for sample 2: sigma(y) = 2153 MPa and sigma(b) = 2165 MPa, with delta = 10%.