PECULIARITIES OF HYDROGEN INTERACTION WITH THE TAl2–xNix LAVES PHASES (T = Zr, Hf)

O.V.Shved,
 
I.I.Bulyk,
 
S.I.Mudry,
 
I.V.Borukh,
 
O.P.Kononiuk
 

Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2018, #09/10
http://www.materials.kiev.ua/article/2661

Abstract

The effect of hydrogen treatment on the phase composition and structure of the Laves phases in the Zr(Hf)–Ni–Al systems has been studied. It is found that ball milling in a planetary mill leads to partial glass formation in the alloys, the Laves phases have nanocrystallites ≈6–14 nm in size, and a phase transition takes place in the HfAl1.4Ni0.6 alloy. The nanocrystallites of the Laves phases refine with increasing grinding time. It is shown that interaction of the as-cast alloys with hydrogen at 3.0 MPa and 950 °С finishes with their homogenization and formation of additional phases, such as Zr2Al3 and Zr6Ni8Al15, for the zirconium alloys. Besides the original phase of MgCu2 structural type, a phase with MgZn2 structure appears in the hafnium alloys. The ball-milled zirconium alloys partially oxidize after the heat treatment in hydrogen.


HIGHLY DISPERSED MICROSTRUCTURE, HYDROGEN TREATMENT, NANOCRYSTALS, PSEUDOBINARY LAVES PHASE