Study of the structure and properties of a workpiece made of Ti-6Al-4V alloy obtained by hot isostatic pressing

One of the promising and widespread methods of powder metallurgy is hot isostatic pressing (HIP), which makes it possible to obtain dense, non-porous workpiece from metal powders with enhanced mechanical characteristics. However, due to the uneven distribution of temperature and pressure during the casting process, an inhomogeneous structure is formed from the periphery to the center of the workpiece, which negatively affects the further operation of the finished product. The paper presents the results of a study of the structure and properties of a blank made of Ti-6Al-4V titanium alloy obtained by the HIP method. Metallographic analysis was performed, and the distribution of microhardness, density, and porosity over the sample section was analyzed. It is established that the structure of the material formed during the HIP process is heterogeneous, and its properties change from the periphery to the center (microhardness and porosity increase, density decreases). It is shown that the reason for the uneven formation of mechanical properties is the presence of a gradient in the volume fraction of the β-phase, while its content in the material of the peripheral part of the workpiece is ~20%, and in the central part — 28%. The results obtained can be applied in assessing the quality of the obtained HIP workpieces made of Ti-6Al-4V titanium alloy, as well as to create computational models of HIP technological processes.

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