Microstructural comparison of hot isostatically pressed Mo[sbnd]10Nb alloys before and after hot rolling

Abstract

In this work, hot isostatic pressing (HIP) and HIP followed by hot rolling (HIP+HR) were employed to process high-performance Mo10Nb alloys, respectively. The relative density, O content, oxide types, grain size and shape, and texture type of HIP-processed Mo10Nb alloys before and after HR were systematically investigated. The results indicate that the relative densities of Mo10Nb alloys prepared by the two methods are both over 98%. The oxygen content of HIP-processed and (HIP+HR)-processed Mo10Nb alloys is 638 ± 38 ppm and 2297 ± 152 ppm, respectively. X-ray photoelectron spectrometry (XPS) confirms that the main oxides in HIP-processed Mo10Nb alloys are MoO2, MoO3, NbO and Nb2O5 while those in (HIP+HR)-processed Mo10Nb alloys are stable MoO3 and Nb2O5 resulting from the oxygen contamination during HR. More importantly, HR crushes large Nb-rich phase particles and elongates equiaxed grain in HIP-processed Mo10Nb alloys. The high temperature during HR leads to the moderate growth of grains. Noteworthy, two weak textures along {001}〈110〉 and {111}<110 > orientations were found in HIP-processed Mo10Nb alloys after HR, which could be caused by the incomplete development of deformation textures and recrystallization textures. This work helps us to clarify the microstructure difference of HIP-processed Mo10Nb alloys before and after HR, which can provide some valuable science and technology guidance for fabrication of refractory alloys by powder metallurgy and the following plastic deformation.