| Title |
Effect of Heating Rate and Porosity on the Microstructure and combustion temperature of NiAl intermetallic compound |
| Abstract |
The effect of heating rate and initial porosity on the ignition temperature, combustion temperature and microstructure of products formed by combustion synthesis was investigated. Ignition temperature increased with increasing heating rate and initial porosity. Temperature rise(ΔT) caused by exothermic reaction decreased with increasing heating rate and decreasing initial porosity. Microstructure of the product formed by 2℃/min. heating rate consisted of Al₃Ni, Al₃Ni₂ precombustion crystal and martensite matrix. Typical polygonal grain structure was observed in specimen produced with initial porosity of 20% and heating rate of 20℃/min. Whereas irregular grain boundary was observed in specimen produced with initial porosity of 53% and heating rate of 600℃/min. |