Al-high Si alloys were designed by the addition of Cu or Mg alloying elements to improve the mechanical properties. It is found that the addition of 1 wt.% Cu or 1 wt.% Mg as strengthening elements significantly impro...Al-high Si alloys were designed by the addition of Cu or Mg alloying elements to improve the mechanical properties. It is found that the addition of 1 wt.% Cu or 1 wt.% Mg as strengthening elements significantly improves the tensile strength by 27.2% and 24.5%, respectively. This phenomenon is attributed to the formation of uniformly dispersed fine particles(Al2Cu and Mg2Si secondary phases) in the Al matrix during hot press sintering of the rapidly solidified(gas atomization) powder. The thermal conductivity of the Al-50 Si alloys is reduced with the addition of Cu or Mg, by only 7.3% and 6.8%, respectively. Therefore, the strength of the Al-50 Si alloys is enhanced while maintaining their excellent thermo-physical properties by adding 1% Cu(Mg).展开更多
SMEMA（Surface Mount Equtpment Manufacturers Association）,即表面组装设备制造商协会的简称,该协会制订了一系列标准,SMEMA接口标准只是其中之一,该标准为表面组装设备之间的pcb板传送提供了协议,表面组装设备必须至少满足该标准...SMEMA（Surface Mount Equtpment Manufacturers Association）,即表面组装设备制造商协会的简称,该协会制订了一系列标准,SMEMA接口标准只是其中之一,该标准为表面组装设备之间的pcb板传送提供了协议,表面组装设备必须至少满足该标准所定义的要求,但该标准并不定义了设备的全部接口。为适合该标准要求,可对设备接口进行适当的设计或者通过专用的转接器来实现。展开更多
文摘Al-high Si alloys were designed by the addition of Cu or Mg alloying elements to improve the mechanical properties. It is found that the addition of 1 wt.% Cu or 1 wt.% Mg as strengthening elements significantly improves the tensile strength by 27.2% and 24.5%, respectively. This phenomenon is attributed to the formation of uniformly dispersed fine particles(Al2Cu and Mg2Si secondary phases) in the Al matrix during hot press sintering of the rapidly solidified(gas atomization) powder. The thermal conductivity of the Al-50 Si alloys is reduced with the addition of Cu or Mg, by only 7.3% and 6.8%, respectively. Therefore, the strength of the Al-50 Si alloys is enhanced while maintaining their excellent thermo-physical properties by adding 1% Cu(Mg).
文摘SMEMA（Surface Mount Equtpment Manufacturers Association）,即表面组装设备制造商协会的简称,该协会制订了一系列标准,SMEMA接口标准只是其中之一,该标准为表面组装设备之间的pcb板传送提供了协议,表面组装设备必须至少满足该标准所定义的要求,但该标准并不定义了设备的全部接口。为适合该标准要求,可对设备接口进行适当的设计或者通过专用的转接器来实现。
