Effect of powder metallurgy method on strength and fracture toughness of NiAl

摘要

Heat-resistant intermetallic alloy NiAI is a good candidate for elevated temperature structural applications, except for its inherent brittleness. Details of the mechanical properties of NiAI have been reviewed recently [1]. The brittleness of NiAI is due to the relatively high non-metallic component of interatomic bonding [2], and anisotropy of active slip systems [3,4]. The <100>{011} slip family predominant at room temperature yields only three independent slip systems and cannot provide macro-plasticity of the polycrystalline NiAI, according to von Mises criteria. It was recently shown that climb, and not activation of secondary slip systems, is responsible for the brittle-to-ductile transition in NiAI [5]. This transition occurs at a relatively low temperature, about 300 °C.