Papers by Keyword: Ni₃Al Intermetallic Compound

Abstract: The results of investigation of the time and power parameters influence of high-temperature synthesis under pressure on the grain structure formation and strength properties of the Ni₃Al intermetallic compound are presented and discussed. Dependences of the grain size in the intermetallic compound synthesized under pressure and its strength properties on the value of the preload on the initial powder mixture (3Ni + Al) and on the delay time of pressure application to the thermoreacting system were determined from the time of initiation of intermetallic compound formation volumetric exothermic reaction.

Abstract: Ni₃Al intermetallic compounds containing Cr was synthesized via Spark Plasma Sintering process. These Ni₃Al intermetallic compounds containing Cr have a nearly full density after sintered at 1100 °C for 5 min under the pressure of 40MPa. Microstructure and hardness of these intermetallic compounds was studied through metallograph observation and micro hardness tests. Their formation and strengthening mechanisms were analyzed and discussed in detail. The influence of the chromium content on corrosion resistance of these intermetallic compounds was analyzed by anode polarization curves. Results show that the corrosion resistance of Ni₃Al intermetallic compounds is upgraded significantly with increasing chromium content.

Abstract: The Ni3Al intermetallic compound is of great interest because of its oxidation, corrosion-resistance, and high melting point. The low-temperature hot press + thermal diffusion process method is a technique that uses the thermal reactive diffusions between the elements that compose the intermetallic compound. In this method the powder mixture is heated and be able to generate the diffusions of the powder elements by keeping the heating temperature comparatively lower temperature with other technique. The authors evaluated the preparation conditions and joining quality in Ni3Al coating layer of particular interest is the residual stress due to the different mechanical properties of the coating and the substrate and its effect on the interface joining quality. It is known that residual stresses were generated by the difference in the coefficient of thermal expansion (CTE) of coating and substrate during cooling process. Such a residual stress caused by the differences of mechanical properties has strong influence on composite material strength. X-ray stress measurement techniques has been developed for experimental determination of residual stresses. In this paper, the Ni3Al intermetallic compound was coated on spheroidal graphite cast iron and austenite stainless steel using the reactive sintering method. Wear characteristics and residual stress on these intermetallic compound layers were investigated to evaluate the effect of substrate materials on coating layer properties.