Enhanced densification of porous nickel aluminide under shock compression

Vacancy Mobility in Nickel Aluminide versus Composition

The fractional concentration of Ni-vacancies in NiAl at high temperature has been determined for compositions between 50 and 53 at.% Ni from measurements using perturbed angular correlation of gamma rays (PAC). The vacancies were detected by quadrupole interactions induced at nearby In/Cd impurity probes present on the Al sublattice in high dilution. One set of measurements was made at high tem...

Equilibrium Defects and Concentrations in Nickel Aluminide

Perturbed angular correlation of gamma rays was applied to determine properties of equilibrium defects in B2 NiAl near the stoichiometric composition. Point defects were detected through quadrupole interactions they induce at In probe atoms on the Al sublattice. Well-resolved signals were observed for probe atoms having zero, one or two Ni-vacancies (VNi) in the first neighbor shell. The fracti...

Shock response of a gamma titanium aluminide

Potential use of -TiAl alloys in aerospace and other structural applications require knowledge of their impact behavior for better evaluation and modeling. In the present study plate impact experiments are conducted using a single-stage gas gun to better understand the shock behavior of the recently developed class of gamma titanium aluminide alloys—the Gamma-Met PX. The Gamma-Met PX showed sup...

The Effects of Beryllium Additions on the Oxidation of Nickel Aluminide and Titanium Aluminide Based Intermetallics

The effects of Be additions on the oxidation behavior of ~-NiAl in moist air at 1000°C and borderline alumina-forming y (TiAI) + Laves Ti-Al-Cr based alloys at 800°C and 1000°C in dry and moist air were investigated. The addition of Be to ~-NiAl suppressed the formation of transient alumina, and resulted in the formation of a protective BeAl20 4 spinel phase. In dry air, the addition of Be to t...

Strength of Polycrystalline Ceramics under Shock Compression