Effect of some consolidation parameters on the microstructure and physical properties of a PM-Ni3Al alloy

Abstract

The aim of this work is to study the viability of using no-destructive techniques to study the effect of consolidation parameters in the microstructure and elastic constants of a PM Ni₃Al with molybdenum additions synthesized by rapid solidification and hot isostatic pressing (HIP). Furthermore the homogeneity of the compacts and presence of pores and cracks were evaluated by X-ray. For this purpose, three capsules of the alloy consolidated by HIP at different temperatures, 900, 1100 and 1250 °C, have been studied using X-ray techniques, ultrasonic measurements and Eddy-current. Parameters such as ultrasonic velocity measurements of longitudinal and transverse waves, the ultrasonic signal attenuation for high frequency, electrical conductivity and density were determined to evaluate the physical constants Eo, Go y µo. The reflected and reverberation signals have been analysed using the Fast Fourier Transformation obtaining for both a frequency spectrum that have been interpreted as Acoustic Materials Signature functions. A lineal increase of E_o and G_o with an increases of the consolidation temperature has been measured which has been related to the capsules densification condition. Similar results have been obtained by measuring the electrical conductivity of the capsules. Thus, the highest value was exhibited by the capsule hipped at 1250 °C indicating that no defects are present and therefore reaching the optimal consolidation temperature.