(1. Department of Engineering, Faculty of Materials Science and Engineering,
Imam Hossein University, Tehran 15816-18711, Iran;
2. Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran 14515775, Iran;
3. Department of Material Engineering, South Tehran Branch, Islamic Azad University, Tehran 1459853849, Iran)
摘 要: 采用擴(kuò)散連接方法在壓力范圍10~35 MPa、溫度430~450 °C、時(shí)間60 min，真空13.3 mPa條件下連接Al 7075和 Mg AZ31合金。采用掃描電子顯微鏡、X射線能譜和X射線衍射分析合金的顯微組織演變、相分析和元素分布。結(jié)果表明:25 MPa為最佳的壓力條件，在此條件下接頭發(fā)生最小的塑性變形；在界面過(guò)渡區(qū)可觀察到含不同金屬間化合物如Al12Mg17, Al3Mg2 和 α(Al)的固溶體反應(yīng)層；隨著溫度的升高，反應(yīng)層的厚度增大，更多的鋁原子擴(kuò)散進(jìn)入鎂合金，且界面朝著鋁合金移動(dòng)；在溫度440 °C、壓力25 MPa下得到最大的結(jié)合強(qiáng)度38 MPa。斷口形貌研究表明，脆性斷裂來(lái)自于Al3Mg2相。
關(guān)鍵字: Al 7075合金；Mg AZ31合金；擴(kuò)散連接；金屬間化合物；界面過(guò)渡區(qū)；顯微組織；力學(xué)性能
（1. Department of Engineering, Faculty of Materials Science and Engineering,
Imam Hossein University, Tehran 15816-18711, Iran;
2. Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran 14515775, Iran;
3. Department of Material Engineering, South Tehran Branch, Islamic Azad University, Tehran 1459853849, Iran）
Abstract:Al 7075 and Mg AZ31 alloys were joined by diffusion bonding method. Joining process was performed in pressure range of 10-35 MPa at temperatures of 430-450 °C for 60 min under a vacuum of 13.3 MPa. The microstructure evaluation, phase analysis and distribution of elements at the interface were done using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The pressure of 25 MPa was determined as the optimum pressure in which the minimum amount of plastic deformation takes place at the joint. Different reaction layers containing intermetallic compounds, such as Al12Mg17, Al3Mg2 and α(Al) solid solution, were observed, in interfacial transition zone (ITZ). Thickness of layers was increased with increasing the operating temperature. According to the results, diffusion of aluminum atoms into magnesium alloy was more and the interface movement towards the Al alloy was observed. The maximum bond strength of 38 MPa was achieved at the temperature of 440 °C and pressure of 25 MPa. Fractography studies indicated that the brittle fracture originated from Al3Mg2 phase.
Key words: Al 7075 alloy; Mg AZ31 alloy; diffusion bonding; intermetallic compounds; interfacial transition zone; microstructure; mechanical properties
