AlSi10Mg(Cu)铸铝合金的热疲劳裂纹萌生及早期扩展行为

The damage evolution under thermal fatigue loading for AlSi10Mg(Cu) cast alloy on the crack initiation and early propagation stage, mainly focusing on the influence of silicon particles on the thermal fatigue crack behaviour. The results show that, thermal fatigue crack origins from the failure interfaces between debonded silicon particles and matrix, that is because of the difference in thermal expansion coefficient between silicon particles and aluminum matrix, thus leading to the misfit of thermal strain, finally caused cyclic stress on the interfaces with fatigue failure. The propagation of thermal fatigue crack related to the growth on both length and width direction, ductile dendrite hinders the propagation of fatigue crack. The result of simulation analysis about the stress distribution around silicon particles during thermal fatigue is given to help discuss the experiment results.