The wear and corrosion properties of SiC p /graphite reinforced copper metal matrix composites (MMCs) fabricated by hot pressing have been evaluated. Electron microscopic studies were conducted to clarify the micromechanisms of wear and corrosion. The experimental results indicate that the hardness and wear loss increase with increasing SiC p content but decrease with increasing graphite content. In particular, the wear loss decreases with increasing graphite up to a content of 5 vol.-% then remains approximately constant as the graphite content is further increased to 7 . 5 vol.-%. The material porosity of the composites increased with the content of foreign particles (SiC p and/or graphite).The composites were immersed in an aqueous solution of 3 . 5 wt.-%NaCl at pH 6?7 for potentiodynamic and corrosion rate measurements. Pure copper exhibited the best corrosion resistance. The Cu/SiC p composite showed lower resistance, and the Cu/SiC p /graphite composite had the lowest resistance to corrosion. The poor corrosive properties of the composites were the result of galvanic and crevice corrosion, which were influenced by residual stress/strain and differences in electrochemical potential between the additions (SiC p and/or graphite) and the copper matrix. Furthermore, the weight loss due to corrosion increased with increasing SiC p and graphite content.CEST/2092

Defects in the specimen of missile engine shell was detected by thermal wave image technology in this paper. In order to gain intuitionistic and accurate space structure image of the detected object, subtracting background and high-frequency emphasized filtering method were used to enhance the image quality. Then the defect was segmented from the background using particle swarm fuzzy clustering algorithm, while the defect size and depth were identified quantitatively. On this basis, 3D reconstruction of the defect by thermal wave image was recognized by Volume Rendering method. The results show that the precision of the defect quantitative identification is higher, and 3D reconstruction result is well, which help us to observe the location and size of defects intuitionisticly.