以鋁接合鋁基碳化矽與銅基碳化矽複合材料之研究

Diffusion bonding of Al/(SiC)p and Cu/(SiC)p metal matrix composite using an aluminum interlayer

林宸緯(Chen-Wei Lin)

指導教授 ： 莊正利

中山醫學大學/健康管理學院/職業安全衛生學系碩士班/碩士(2013年)

https://doi.org/10.6834/CSMU.2013.00006

摘要

金屬基複合材料若採用傳統之熔融接合法，易產生高溫、強光及煙燻等危害因子，導致勞工灼傷、白內障、塵肺症等職業傷害。熔銲金屬基複合材料過程中，熔融金屬基材與強化材之密度差異而造成強化材分佈不均，且金屬基材之接合處可能產生介金屬間化合物(Intermetallic compound, IMC)，降低接合界面之強度及品質。故採用固相擴散接合(Solid state diffusion bonding)法，其製程溫度均低於母材與強化材之熔點溫度，可降低熱曝露所產生之危害，亦可避免金屬基複合材料中碳化矽分佈不均與降低介金屬化合物之生成量，進而提高金屬基複合材料之接合品質。本研究採用固相擴散接合法，接合鋁基碳化矽與銅基碳化矽複合材料，選用厚度為50μm之鋁箔為接合層材料，接合實驗之控制參數包括接合溫度(450℃-650℃)、接合時間(30-120min)與接合負荷(220MPa)，並改變金屬基複合材料中強化材之重量百分比，驗證強化材含量對金屬基複合材料接合品質之影響。金屬基複合材料接合後，以光學顯微鏡與電子顯微鏡觀察接合界面之微觀組織，以剪切實驗測試接合試片之強度，並輔以破斷面觀察，說明接合試片之破斷模式，成份分析以能量散射光譜儀，分析接合界面之組成與可能出現之介金屬化合物。
由實驗結果得知以鋁作為鋁基碳化矽與銅基碳化矽複合材料之接合層材料，可成功接合鋁基碳化矽與銅基碳化矽複合材料，且接合強度隨製程溫度與接合時間提升而增大，顯示較高製程溫度與較長接合時間可有效促進接合界面之原子進行交互擴散，進而提高其接合強度。但製程溫度上升至650℃，接合界面之顯微結構發現部份碳化矽強化材聚集於鋁接合層與鋁基碳化矽複合材料接合側，推論其主要形成原因為650℃之製程溫度過高，致使部份鋁基材產生軟化而流動且經接合負荷作用下，部份鋁基材被擠出模具外，造成碳化矽強化材聚集，顯示製程溫度不宜過於接近金屬基材之熔點溫度，因此採用600℃之製程溫度，避免鋁基材過於接近熔點溫度所產生之缺陷。製程溫度為600℃之接合試片經剪切試驗後，剪切強度達26.7MPa；隨持溫時間增加，接合試片間之原子交互擴散率及接合層厚度亦隨之增加，有效提高接合試片之剪切強度，但持溫時間過長易使接合層厚度寬大，造成接合試片之剪切強度下降，故持溫時間90分鐘可達最高剪切強度值為43.7MPa；碳化矽重量百分比之增加有助於提升接合試片之剪切強度，當碳化矽強化材含量15wt.%時，最高剪切強度值達80.6MPa，當碳化矽重量百分比持續增加，接合試片之剪切強度逐漸下降，其原因為包覆碳化矽強化材周圍之金屬基材含量減少，造成鋁基碳化矽與銅基碳化矽複合材料中碳化矽強化材未能與金屬基材產生良好的鍵結。本實驗結果顯示藉由熱壓法可提高鋁基碳化矽複合材料與銅基碳化矽複合材料之接合強度，降低傳統之熔融接合法所產生之危害，提供良好之作業環境，確保作業人員之安全。

關鍵字

固相擴散接合 ； 鋁基碳化矽複合材料 ； 銅基碳化矽複合材料

並列摘要

The traditional fusion welding process was widely used to join the metal matrix composites (MMC). An elevated temperature is required to melt the metal matrix and then to achieve welding. Some hazards formed easily in the welding process such as high temperature, fumes and toxic gases, which harms the welder’s safety. In general, the density of reinforcement is lighter than that of metal matrix, thus, a segregation defect would form when the fusion welding process was applied to join the MMCs. The solid state diffusion bonding process is expected to reduce the bonding temperature and to improve bonding quality of MMCs.
In this study, the solid state diffusion bonding process was used to join Al/(SiC)P and Cu/(SiC)P with an interlayer. The aluminum foil with the thickness of 50um was selected as the interlayer. The major bonding parameters of solid state diffusion bonding, bonding time, bonding temperature and the fraction of reinforcements were investigated. After Al/(SiC)P and Cu/(SiC)P bonded together, the optical microscopy and scanning electron microscopy were conducted to observe the microstructure of bonding interface and to evaluate the fracture mode. The bonding strength of Al/(SiC)P and Cu/(SiC)P was determined using a shear test.
According to the experimental results, the Al/(SiC)P and Cu/(SiC)P can be bonded successfully with an interlayer of aluminum foil by solid diffusion bonding process. The bonding strength increases with the increasing bonding temperature and bonding time. This experimental result implies that higher bonding temperature and extending bonding time promoted the atomic interdiffusion, and the bonding strength is thus enhanced. When the bonding temperature increased to 650°C, the interlayer soften and the flowability increased, larger reinforcements pile up at bonding interface between the Al/(SiC)P and the interlayer. The bonding strength is thus degrading, indicating the bonding temperature should not be closed to the melting point of metal matrix and the interlayer. As increasing reinforcement fraction in the range of 5wt% to 15wt%, the bonding strength increases with the reinforcement fraction, and the highest bonding strength is 80.6 MPa approximately. Adding appropriate fraction of reinforcements is an effective way to improve the bonding strength. However, the bonding strength gradually degrades when an exceeding reinforcement was added. The metal matrix is insufficient to form a sound bond between the reinforcements and the metal matrix. A porosity defect or cracks would be formed between reinforcements and metal matrix resulting in a lower bonding strength.

並列關鍵字

solid diffusion bonding ； Al/(SiC)p metal matrix composites ； Cu/(SiC)p metal matrix composites

參考文獻

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