Effect of niobium on the microstructure, hydrogen embrittlement, and hydrogen permeability of Nb xHf (1− x)/2 Ni (1− x)/2 ternary alloys

Abstract

The influence of niobium (Nb) on the microstructure, hydrogen embrittlement, and hydrogen permeability of the Nb x Hf (1− x)/2 Ni (1− x)/2 ternary alloys has been studied in particular. The results show that the quantity of the primary (Nb, Hf) phase decreases with the increase of Nb content from 14 mol% to 16 mol%, and then increases with the increase of the Nb content from 16 mol% to 40 mol%. The Nb 14Hf 43Ni 43 alloy is brittle at all temperatures from 523 K to 673 K, as it possesses the largest amount of the B f-HfNi compound; however, the Nb 40Hf 30Ni 30 alloy has high resistance to hydrogen embrittlement at all temperatures from 523 K to 673 K, as it possesses the largest amount of the primary (Nb, Hf) phase. The hydrogen permeability ( Φ) increases with the increase in Nb content, as the quantity of the primary (Nb, Hf) phase in the Nb x Hf (1− x)/2 Ni (1− x)/2 ternary alloys also increases with the increase in Nb content.