The steady-state creep rate of Ni-base metallic foams, with superalloy composition (in wt. pct) Ni7.8∼9.1Al (relative density, ρ = 2.5-2.6) and Ni-13.5∼16.6Cr-5.1∼8.9Al (ρ = 2.8∼3.0), was measured under a range of temperatures (680∼825°C) and applied stresses (0.1∼0.3 MPa), and compared with that of NiAl intermetallic foams (ρ = 5.3). The stress exponent and activation energy are within the exp...

The aphase is rich in Ta. When the Ta concentration is less than 14%N, adoes not interfere with the slip mechanism; when the Ta concentration is more than 15%, ainterferes with the slip mechanism. The coherent at-Co 3Ta phase forms at Ta concentrations of less than 15%1, whereas incoherent 7-Co2Ta forms only at higher Ta concentrations. The interface between aand the matrix is an important fact...

The purpose of this study is to develop a numerical approach to simulate the creep cracking of a Ni-base superalloy. The approach is based in continuum damage mechanics (CDM) and uses the classic Kachanov-Rabotnov constitutive equations for creep deformation and damage evolution. Creep damage takes the form of defects such as microcracks, cavities, voids, etc. A numerical crack growth algorithm...

A new computational tool has been developed to model, discover, and optimize new alloys that simultaneously satisfy up to eleven physical criteria. An artificial neural network is trained from pre-existing materials data that enables the prediction of individual material properties both as a function of composition and heat treatment routine, which allows it to optimize the material properties ...

Experimental details of atom probe field ion microscopy (APFIM) of a Ni-16Cr-9Fe alloy are presented. In particular, studies concerning analysis of intergranular carbides and borides and segregation to grain boundaries are described. It was found that NiZ3B6 precipitates are very sensitive to preferential field evaporation, which necessitates optimization of the analysis conditions. In the FIM ...