| 摘要: | 本研究藉由光學顯微鏡（OM）、熱差掃描分析儀（DSC）、電子顯微鏡（SEM）來分析Sb改良和固溶時效對4Y32鋁合金（Al-11.2Si-3Cu-0.5Mg-0.5Mn）微結構、機械性質、與抗磨耗性質之影響；結果顯示，經Sb改良後，可獲得細小層狀（Lamellar）鑄態共晶微結構；均質化後共晶矽發生細化與球化，經熱軋後，共晶矽發生更顯著之細化與球化，而共晶矽隨固溶時間增加而粗化。經505℃*0.5hr固溶淬火處理，合金之強化固溶原子已可充分回溶至Al基地；且Sb的改良並不會影響合金之析出動力或析出量，但Sb的添加，可細化T6態合金之共晶矽。
藉由改良劑(Sb)的添加與固溶時效等處理，可以調控4Y32鋁合金之共晶矽(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。結合Sb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，將可提升4Y32鋁合金之抗磨耗。當磨耗過程中，合金表面會形成一保護性MML氧化層，經Sb改良合金具有較高穩定性，而MML氧化層穩定性隨厚度增加而降低，當MML氧化層因裂縫成長傳遞而剝落，合金磨耗機制由研磨磨耗(Abrasive wear)轉為分層磨耗(Delamination wear)。
;The effect of Sb modification, solution and aging treatment on the microstructure, mechanical properties and anti-wear properties of 4Y32（Al-11.2Si-3Cu-0.5Mg-0.5Mn）aluminum alloy was demonstrated by Optical Microscopy（OM）, Differential Scanning Calorimeter（DSC）,and Scanning Electron Microscopy（SEM）. The results showed that Sb-modified alloy presented a fine lamellar eutectic microstructure. After homogenization, the eutectic silicon undergoes refinement and spheroidization, and hot-rolling caused eutectic silicon undergoes more significant refinement and spheroidization. The eutectic silicon coarsens with increasing solid solution time. After 505℃*0.5hr solution treatment and water quenching, the strengthened solid solution atoms of the alloy can be fully dissolved into the α-Al matrix. The element Sb will not affect the precipitation kinetics or precipitation quantity of the alloy, but the addition of Sb can be refined eutectic silicon of T6 alloy.
Through the addition of modifier (Sb) and solution aging treatments, the morphology and hardness of eutectic silicon of 4Y32 aluminum alloy can be modified. When the hardness of the alloy is same, the eutectic silicon becomes thinner and more resistant to wear. When the size of eutectic silicon is same, the higher the hardness of the alloy, the more resistant it is to wear. Combined with the Sb-modifier, reduction of solution time, and peak aging (T6) heat treatment, the finest eutectic silicon and the highest alloy hardness can be obtained, which will increase the wear resistance of 4Y32 aluminum alloy. During the wear process, a protective oxide layer which is called Mechanical Mixed Layer (MML) is formed on the surface of the alloy. The Sb modified alloy has higher stability, and the stability of the MML decreases with increasing thickness. When the MML peels off due to crack growth and transmission, the wear mechanism is changed from abrasive wear to delamination wear. |
