Effect of Trace Addition of Sr and Be to the Microshrinkage and Contraction of 319 Aluminum Alloys

• Main Authors: Wu, Ying-Chang, 吳穎昌
• Other Authors: Lee Sheng-Long
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/24276127846991200945

碩士 === 國立中央大學 === 機械工程學系 === 85 === This research is to study effect of trace addition of Sr and Be to the microshrinkage and contraction of 319 aluminum alloys. The change of microshrinkage and contraction investigates by optical microscopy, Tatur test, and differential thermal analysis. The result indicates addition Sr or Be is reduce the apparent density, increase the volume of microshrinkage and decrease the volume of pipe, increase and round the volume of microshrinkage. Addition Sr induced eutectic undercooling and Be raise the liquidus temperatures, both of then promote an increase in the freezing range. The decrease the pipe volume and increase microshrinkage volume are due to interdendritic feeding difficulties caused by the increase freezing range. It appears that the exact level Sr and Be does not presents increase the amount of micorshrinkage.