本研究中將探討鋯基與鋯銅基金屬玻璃薄膜應用於7075-T6高強度鋁合金疲勞性質提升之研究。在鋁合金試片上濺鍍一層厚度為200nm的（Zr53Cu30Ni9Al8）99.5Si0.5與（Zr42Cu42Al8Ag8）99.5Si0.5薄膜，及鋁合金試片在三種條件下分別進行疲勞測試，鋯基鍍膜與鋯銅基鍍膜的鋁合金疲勞壽命在250 MPa的應力下分別為5.0×106次與 >107次，相較於未鍍膜的鋁合金試片分別提升了21.7倍與44.5倍。另外在疲勞限應力上之表現，則分別提升了56.7 %與66.7 %。由上述結果可以得知金屬玻璃薄膜對鋁合金疲勞性質有顯著的提升功效。再者，表面粗糙度、薄膜在基板上的附著力、薄膜本身的機械強度與硬度以及壓縮殘留應力對疲勞性質的提升存在關鍵性的影響。經由SEM觀察發現非晶質鍍膜能有效的抑制offset及裂隙在基板張力面的形成。相較於鋯基鍍膜，鋯銅基鍍膜具有較佳的抗疲勞能力，在250 MPa的應力下，疲勞壽命約為鋯基鍍膜的2倍，此乃由於鋯銅基鍍膜的硬度、強度均較高且具較佳的塑性，所以對於疲勞性質之提升略優於鋯基鍍膜。在本論文中我們也藉由各項儀器的分析來了解超薄鍍膜的特性並建立金屬玻璃鍍膜提升疲勞性質的機制；希望進一步將金屬玻璃鍍膜推廣應用到航太、汽車工業、自行車等交通器械之疲勞性質的提升。 We proposed with the Zr-based and Zr-Cu based metallic glass thin film (MGTF) as promising coating for aluminum alloy fatigue property enhancement. According to the four-point-bending fatigue results, 7075-T6 aluminum alloy with a 200-nm-thick Zr-based MGTF improved its fatigue life cycle 22 times at a stress level of 250 MPa than the bare one. And the other fatigue life cycle of Zr-Cu based MGTF is further improved 44 times which ups to 107 cycles. The improvements of MGTF coating samples in fatigue limit were 235 MPa (56.7 % increase) and 250 MPa (66.7 % increase) for Zr-based and Zr-Cu based glass-forming film, respectively, and 150 MPa for uncoated sample. The films actually restrict the surface offsets and cracks propagating during the fatigue test. Zr-Cu based glass-forming film have better fatigue resistance than Zr-based MGTF, the fatigue life had improved by more than 2 times under a stress of 250 MPa, due to higher hardness and strength, better plasticity, thus it exhibits better improvement in fatigue property. A 50-nm-thick Titanium buffer layer between the film and the substrate was reported adhesion enhancement. The superior mechanical properties of MGTF, such as high strength and good bending ductility, coupled with good adhesion between the film and the substrate as well as the reduced surface roughness, and high compressive residual stress of the metallic film yield the fatigue property improvement of aluminum alloy. Thus demonstrating MGTF as promising coating materials for improving the fatigue properties of materials, and further applied to aerospace, automobile industry and bicycle manufacturing etc.
