添加Zn元素對Al/SiCp金屬基複合材料熱壓接合之影響

Study on the Influence of Zn on the Bonding Strength of Al/(SiC)p Metal Matrix Composite

游捷閎(Chieh-Hung Yu)

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(2017年)

摘要

傳統電弧銲接製程進行金屬基複合材料接合之優點為成本低廉、快速、技術取得容易等，但電弧銲接後易產生偏析、氣孔、裂縫、夾渣等缺陷，進而造成材料接合強度衰退，而熱壓法是一種可使用低於金屬基材熔點之溫度進行金屬基複合材料接合之固態接合製程，同時可避免以電弧銲接接合金屬基複合材料所造成之缺陷，本研究擬於鋁基碳化矽複合材料於熱壓接合時，加入低熔點之鋅於填料中，期望提高其接合性能。
選用平均粒徑為30 μm之鋁粉及40 μm之碳化矽顆粒，以燒結溫度400℃、燒結壓力400 MPa、持溫時間30分鐘製作Al-20SiC複合材料，並以鋅含量0 wt.%-40 wt.%比例加入填料中進行接合。接合製程主要參數分別為接合溫度420℃-600℃、接合壓力220 MPa、持溫時間30-120分鐘進行鋁基碳化矽複合材料之熱壓接合，並進行微結構之觀察及機械性質之測試，用以評估其接合性能。
比較不同鋅含量填料對接合之影響，鋅含量為20 wt.%之接合試片因具共晶反應而強化，且接合界面完整未發現裂縫等缺陷，具較佳剪切強度，其硬度也較相同接合參數下，未添加鋅填料進行接合後試片之硬度顯著提升。由熱差分析儀分析結果得知，填料金屬基材之熔點隨鋅含量增加而降低，且於金屬基材中產生共晶反應，顯示鋅含量有助於降低填料熔點與強化基材強度；鋁基碳化矽金屬基複合材料於不同接合時間後，發現過長接合時間使晶粒粗化，接合界面發現裂縫缺陷，導致剪切強度及硬度降低；以不同接合溫度進行接合，發現接合溫度過低易造成鋁基材之鍵結不佳與鋅團聚之缺陷，致使接合試片之剪切強度及硬度降低，提高接合溫度可提高金屬基材之鍵結強度與鋅元素之擴散，有助於接合試片剪切強度之提升；使用接合填料有助於彌補接合界面平整度，減少接合界面孔隙，提升剪切強度，且使用添加低熔點之鋅金屬填料可降低金屬基材之接合溫度，有效提升金屬基複合材料之接合強度。
綜整相關實驗與分析結果得知添加低熔點鋅金屬於填料中，有助提升金屬基複合材料之接合。

關鍵字

Al/(SiC)p金屬基複合材料 ； 接合填料 ； 固態熱壓接合製程

並列摘要

The traditional arc welding process has several advantages with low cost, time efficiency and easy access. However, defects of segregation, porosity, cracks and slags would be formed and the joining strength was then degraded for the arc welding applied to join the metal matrix compositions (MMCs). The hot pressing is a solid state bonding process that could be used to join the MMCs below the melting point of the metal matrix, and then defects for the arc welding used to join MMCs would be avoided. To obtain a sound joint with sufficient strength, the low melting point of zinc was added to filler and the hot pressing were conducted to join Al/(SiC)p MMCs in this work.
The 30 μm in mean particle size of aluminum powder and 40 μm in mean particle size of silicon carbide were slected to fabricate the Al/(SiC)p MMC. The main parameters of Al/(SiC)p MMC were 400℃ in sintering temperature, 400 MPa in sintering pressure and 30 minute in sintering duration. Then zinc was added to Al/(SiC)p mixed powder from 0 wt.%- 40 wt.% as the filler. The bonding temperature of 420℃- 600℃, 220 MPa of bonding load, and bonding duration was set from 30- 120 minute to join the Al/(SiC)p MMCs using hot pressing process. The microstructure and mechanical properties were determined to evaluate bonding performance of Al/(SiC)p MMCs.
The melting point of metal matrix decreased with increasing the zinc content in the filler due to eutectic bonding was formed between the aluminum and the zinc. A sound joint with the high bonding strength was achieved for the filler with zinc was used to join Al/(SiC)p MMCs. Neither cracks nor delaminations were found at bonding interface and the eutectic reaction can be found in the microstructure. The optimum content of zinc in the filler was 20 wt% in this work. The crack was found in the bonding interface between the Al/(SiC)p MMC and the filler when the content of zinc exceeded 40 wt%. A high level oxygen can be found near the crack, indicating the zinc oxide would lead the crack to form and the bonding performance was degraded. Extending bonding duration resulted in grain coarsening and then degraded in bonding strength and hardness. The bonding performance was improved significantly when the elevated bonding temperature was used to join Al/(SiC)p MMCs. An elevated boning temperature provided sufficient thermal energy to make a sound bonding between the metal matrix and the SiC enforcement. A great bonding performance of Al/(SiC)p MMCs can be achieved by the hot pressing process combined the filler with a low melting point of zinc content.

並列關鍵字

Al/(SiC)p metal matrix composites ； bonding fillers ； hot press

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