Interfacial Stress in a Carbon-to-Metal Bond Joint under Thermal Shock Loading

The duplex bond joint consisting of a metallic substrate armored with carbon-base materials is a promising candidate configuration for application to high heat flux operations. When a bond joint is subjectedto thermal loadings, significant thermal stresses may develop due to mismatch of the thermal expansioncoefficients. Stress intensification occurs near the free surface edge of the interface, sometimes showingsingularity. The singular stress fields are critical for understanding the loading nature of the bond interfacein a joint system.In this paper, thermal stresses in the bond interface of a carbon-to-molybdenum joint element were investigated.A high heat flux (HHF) pulse was assumed as the reference load history to simulate the thermalshock condition. The thermomechanical behavior was described quantitatively in terms of the stressintensity factor.The stress solutions of the singular field computed by the theoretical approach showed a good agreementwith the numerical results of the finite element analysis. The stress intensity factor of the singular stressfields near the free surface edge of the interface showed a time variation similar to that of the bulk stress. Thetemperature gradient induced by the transient HHF load affected the overall interfacial stress only slightly. © 1997, ASM International.