Effect of Mg、Cu content on mechanical properties of Al-14.5Si-Cu-Mg alloys

• Main Authors: Meng-Hsiung Hsieh, 謝孟雄
• Other Authors: Sheng-Long Lee
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/78800304991931335104

碩士 === 國立中央大學 === 機械工程研究所 === 92 === The effect of Mg、Cu content on mechanical properties of Al-14.5Si- 4.5Cu alloys were investigated. Optical microscopy (OM)， electron probe X-ray microanalyzer (EPMA), electrical conductivity meter (%IACS), differential scanning calorimeter (DSC) and scanning electron microscopy (SEM) were used to monitor the variation of microstructure . The results show that increasing Mg content contribute to transformation of β-Al5FeSi needles into the Al8Mg3FeSi6 compacted Chinese script phase. That Mg content exceeds the solubility under solution temperature lowers the percentage of Mg、Cu atoms dissolving into the Al-matrix during solution treatment. This reduces amounts of precipitates and increasement of hardness after artificial ageing, otherwise, tensile properties perform better due to reduction of the number of β-Al5FeSi needles. Decreasing Cu content reduces the effect of precipitation hardening, but tensile properties are promoted due to the transformation of β-Al5FeSi needles into the Al8Mg3FeSi6 compacted Chinese script phase.