A sandwich structured composite containing a hypereutectic high chromium cast iron (HCCI) core and low carbon steel (LCS) claddings was successfully fabricated by centrifugal casting and hot rolling process, and then a series of heat treatments were employed to optimise the performance of the composites. The evolution of microstructures and microhardness of as cast, hot rolled and heat treated specimens were investigated. The results showed that the interfaces combined well with a good metallurgical bonding before hot rolling. Etuectic carbides are crushed, refined obviously and become more isolated. There is not obvious break between primary carbides. The hardness of hot rolled HCCI is 62 HRC, which is higher than that of as cast HCCI (56 HRC) due to the broken and diffusely distributed carbides. The hardness of hot rolled HCCI can reach up to 69 HRC or above after air quenching. The average impact toughness of LCS/HCCI composite could reach up to 10?1 J cm 22 , which was almost three times that of the as cast sample. Glide lamellas were observed among the interface due to the stagger of LCS and HCCI.

Due to the increased use of lightweight sheet materials, there has been a signicant increase in the use of self-pierce riveting. This paper deals with the strength and fracture mechanism of single-lap self-pierce riveted joints. The online window technique was introduced in the single-lap self-pierce riveting processes for evaluating the quality of joints. Signals obtained from sensors were amplied and transferred to the data acquisition system which measures, processes and saves the signals. Monotonic tensile tests were carried out to measure the ultimate tensile strengths for the single-lap self-pierce riveted joints. For investigating the fracture mechanism of the singlelap self-pierce riveted joints, the electrolytic polishing and anode lm coating were used for dealing with the cross-section. The dierential interference contrast method was used for observing the micro-structure of the crosssection of the joints. The distribution of the hardness in the cross-section of the single-lap self-pierce riveted joints was also studied. The normal hypothesis tests were performed to examine the rationality of the test data.