Peculiarities of Pore Structure Formation upon Zr–Ti–Nb Alloys Synthesis Using Hydrogenated Powder Blends
D. V. Oryshych, O. M. Ivasishin, P. E. Markovsky, D. G. Savvakin, O. O. Stasiuk, V. I. Bondarchuk
G. V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03142 Kyiv, Ukraine
Received: 21.07.2020. Download: PDF
The volume changes and microstructure evolution of heterogeneous powder blends are investigated at different stages of Zr–Ti–Nb alloys synthesis. The factors of the pore system transformation during sintering of powder blends are determined. Hydrogenated and non-hydrogenated powders demonstrate different volume changes on heating (decrease in the volume of hydride particles during hydrogen desorption and thermal expansion of non-hydrogenated particles). The difference in volume changes at insufficient bonding forces between particles, especially ZrH$_2$, cause creation of gaps between compacted powders, while Kirkendall’s porosity on chemical homogenization makes an additional contribution to residual porosity. The residual porosity can be reduced by using hydrogenated powders only (TiH$_2$, ZrH$_2$, hydrogenated Zr–Nb and Ti–Nb master alloys), which provides similar volume effects during hydrogen desorption from all components of the system and reduces the contribution of Kirkendall’s porosity.
Key words: hydrogenated powders, volume changes, microstructure, sintering, porosity.
PACS: 61.43.Gt, 61.66.Dk, 61.72.Ff, 62.20.-x, 66.30.-h, 81.05.Bx, 81.05.Rm, 81.20.Ev
Citation: D. V. Oryshych, O. M. Ivasishin, P. E. Markovsky, D. G. Savvakin, O. O. Stasiuk, and V. I. Bondarchuk, Peculiarities of Pore Structure Formation upon Zr–Ti–Nb Alloys Synthesis Using Hydrogenated Powder Blends, Metallofiz. Noveishie Tekhnol., 42, No. 12: 1681—1700 (2020) (in Ukrainian)