Effect of Heating Rate on the Microstructure and Mechanical Properties of Spark Plasma Sintered CNTs Reinforced Nickel Aluminide

摘要

Powder metallurgy method was used to consolidate nickel aluminide reinforced multi-walled carbon nanotubes through planetary ball mill in order to facilitate the effective dispersion of carbon nanotubes (CNTs). In this investigation, 0.5 wt% of CNTs was added to the powder mixture of nickel and aluminum through two ball milling processes: low energy ball mill (LEBM) and high energy ball mill (HEBM). The bulk composites were synthesized by spark plasma sintering (SPS) at constant temperature, holding time, pressure of 32 MPa, 800 °C and 5 min respectively. The heating rate was varied between 50 and 150 °C/min. Microstructural evolutions of the composites were studied and densification of the composites was improved with increase in heating rate but depreciated as the heating rate was further increased. Vickers microhardness values of the fabricated composites were enhanced with increase in heating rate.