Alumina/NiCu Laminate under Thermal Shock up to 1000°C: I, Experimental

The mechanical behavior of an alumina/NiCu laminate under thermal shock loading was investigated. The maximum thermal shock temperature was 1000°C. The laminate architecture was the cause of a basic change in the cracking mechanisms, manifested in a dramatic increase in the mechanical residual strength over that of monolithic alumina. The laminated system was constructed by alternating alumina layers coated with copper films with nickel interlayers and joining them by a combination of liquid-state (brazing) and solid-state (diffusion) bonding. The material system was tested by water quenching square-shaped laminated specimens initially at temperatures of up to 1000°C. Three-point bending tests revealed the mechanical strength before and after thermal shock, and SEM analysis described the damage mechanisms and the extent of debonding at the alumina/NiCu interfaces.