| 摘要: | 本研究藉由光學顯微鏡(OM)、電子顯微鏡(SEM)、電子微探儀(FE-EPMA)、導電度量測(%IACS)及影像分析等觀察Al-11Si-3Cu-0.5Mg合金之微結構，並結合硬度機與磨耗性質之量測，探討共晶矽形貌及合金硬度對Al-11Si-3Cu-0.5Mg合金微結構與磨耗性質之影響，結果顯示，經Sb及Sr改良後，鑄態共晶矽形貌分別為層狀(Lamellar)與更細小之纖維狀(Fibrous)結構；經均質化處理後，Sr改良之共晶矽略微粗化，Sb改良者則因分段而細化，而所有鑄態存在之共晶析出相幾乎均回溶至鋁基地。藉由改良劑(Sr、Sb)的添加、熱軋塑性加工與固溶時效處理等方法，可以調控合金之共晶矽(粗細)形貌與硬度變化，當合金硬度相同時，共晶矽愈細化愈抗磨耗；當合金共晶矽尺寸相同時，合金硬度愈高愈抗磨耗。而磨耗過程中，合金表面會形成一保護性氧化層(機械混合層MML)，經Sr改良之MML保護氧化層，具有比經Sb改良合金為高之穩定性，且較不易破裂。研究發現藉由Sr的改良、降低固溶時間，及頂時效(T6)熱處理等之結合，可以獲得最細共晶矽與最高之合金硬度，將可使Al-11Si-3Cu-0.5Mg合金具有最佳之抗磨耗。;In this study, optical microscope (OM), electron microscope(SEM), electron probe X-ray micro-analyzer (FE-EPMA), electrical conductivity meter (% IACS), Image Analysis, hardness test and wear test to analyze the microstructure of the wrought Al-11Si-3Cu-0.5Mg alloys, and discuss the effect of eutectic silicon morphology and alloy hardness on wear properties. The results shows that the morphology of eutectic silicon modified by strontium and antimony is lamellar and finer fibrous structure in the as-cast alloy, respectively. After homogenization, eutectic silicon is slightly coarsened by Sr-modified and refined by Sb-modified because of fragmentation, and the eutectic phases mostly dissolved during homogenization. Eutectic silicon morphology and hardness can be controlled by the addition of modifiers, hot rolling and solution aging treatment. When the hardness of the alloy is the same, the finer eutectic silicon have better wear resistant, and when the morphology of the silicon is the same, so does the higher hardness alloy. Mechanically mixed layers (MML), which form on the surface during the wear test, The MML has higher stability and lower cracking tendancy in Sr-modified than in Sb-modified. The study found that, wear behavior of Al-11Si-3Cu-0.5Mg alloy enhanced by a combination with Sr-modified, lower the solution time and T6 peak aging. |
