Ni composites reinforced with ultrafine and uniform TiCx and Cr3C2 particles in situ: Enhanced properties and a well-matched interface

Abstract

Ni composites were reinforced with ultrafine and uniform TiCx and Cr3C2 particles in situ via reactive pressure sintering using 15 vol%Ti2AlC, 15 vol%Cr2AlC, Ni powders. An improved powder preparation process through high-energy ball milling and freeze drying was adopted. Ultrafine TiCx or Cr3C2 particles (about 200 nm) were combined with about 320 nm Ni grains within a uniform microstructure. Considering the matrix grains, intragranular nanoscale TiCx and Cr3C2 were found in Ni grains, with a dispersed distribution of γ′-Ni3(Al,Ti) nanospheres. The interface between Ni and TiCx was semicoherent, whereas Cr3C2 and Ni had a well-matched interface. Ni composites dispersedly strengthened by in situ uniformly distributed TiCx and Cr3C2 with a high ceramic fraction of about 15 vol% possess noticeable 1.378 GPa yield strength. This strategy can be used to design ultrafine, uniform, high-performance composites for structural application.