Mechanical behavior of α-Al2O3-coated SiC particle reinforced nickel matrix composites

• SiC particles were coated with α-Al2O3 by sol–gel technology.
• The Ni/CSp composite was fabricated by electrodeposition.
• The yield strength of Ni/CSp was increased by more than six times of pure Ni at 600 °C.
• SiC enhanced strength by inhibiting grain growth and interacting with dislocations.
• Cracking of coated particles demonstrated the result of load transfer strengthening.

The influence of particle reinforcement on the mechanical behavior of nickel matrix composites with heat treatment at 600 °C was studied. The Ni/SiC composite, with SiC particles coated with sol–gel α-Al2O3, was fabricated by electrodeposition. Through the material design of the introduction of the α-Al2O3 coatings, the coated SiC particles still remain in the composite without reacting with nickel, so that the true effect of SiC particles on the mechanical behavior of the nickel matrix composite with heat treatment can be revealed. The result showed that the presence of coated SiC particles enhanced strength by inhibiting grain growth, while simultaneously interacting with dislocations. The yield strength of 338 MPa was achieved in the composite, increased by more than six times compared to pure nickel. Furthermore, the fracture mechanisms were discussed. Cracking of the coated SiC particles was observed in the composite, resulting in load transfer strengthening.