The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the Si C particulate was analyzed. The microstructures of...The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the Si C particulate was analyzed. The microstructures of different parts of the shell were observed by scanning electron microscopy and optical microscopy, and the thermophysical and mechanical properties of the shell were tested. The results show that there exists the segregation phenomenon between the Si C particulate and the liquid phase during thixoforming, the liquid phase flows from the shell, and the Si C particles accumulate at the bottom of the shell. The volume fraction of Si C decreases gradually from the bottom to the walls. Accordingly, the thermal conductivities of bottom center and walls are 178 and 164 W·m-1·K-1, the coefficients of thermal expansion(CTE) are 8.2×10-6 and 12.6×10-6 K-1, respectively. The flexural strength decreases slightly from 437 to 347 MPa. The microstructures and properties of the shell show gradient distribution.展开更多
Particulate composites based on isotactic polypropylene(iPP) and titanium dioxide(TiO 2) have been prepared and their morphology and thermal behavior investigated by scanning electron microscopy(SEM), differential sca...Particulate composites based on isotactic polypropylene(iPP) and titanium dioxide(TiO 2) have been prepared and their morphology and thermal behavior investigated by scanning electron microscopy(SEM), differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). Tensile tests were performed to assess the influence of TiO 2 on the mechanical properties of the iPP.展开更多
文摘The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the Si C particulate was analyzed. The microstructures of different parts of the shell were observed by scanning electron microscopy and optical microscopy, and the thermophysical and mechanical properties of the shell were tested. The results show that there exists the segregation phenomenon between the Si C particulate and the liquid phase during thixoforming, the liquid phase flows from the shell, and the Si C particles accumulate at the bottom of the shell. The volume fraction of Si C decreases gradually from the bottom to the walls. Accordingly, the thermal conductivities of bottom center and walls are 178 and 164 W·m-1·K-1, the coefficients of thermal expansion(CTE) are 8.2×10-6 and 12.6×10-6 K-1, respectively. The flexural strength decreases slightly from 437 to 347 MPa. The microstructures and properties of the shell show gradient distribution.
文摘Particulate composites based on isotactic polypropylene(iPP) and titanium dioxide(TiO 2) have been prepared and their morphology and thermal behavior investigated by scanning electron microscopy(SEM), differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). Tensile tests were performed to assess the influence of TiO 2 on the mechanical properties of the iPP.
