(西安科技大學(xué) 材料科學(xué)與工程學(xué)院，西安 710054)
摘 要: 采用過渡液相擴(kuò)散焊技術(shù)對鎂合金AZ31B和Cu異種金屬進(jìn)行焊接，利用掃描電鏡(SEM)、顯微硬度測試及X射線衍射(XRD)對AZ31B/Cu接頭界面附近的顯微組織及性能進(jìn)行研究。結(jié)果表明，在500 ℃、40 min、2.5 MPa條件下，AZ31B/Cu接頭形成了寬度約為450 μm的擴(kuò)散區(qū)。AZ31B/Cu材料接頭的顯微組織依次為α-Mg和沿其晶界析出相Mg17(Cu, Al)12組成的晶界滲透層/(α-Mg+Mg2Cu)共晶層/Cu2Mg金屬間化合物層/(α-Mg+Mg2Cu)共晶層/Cu(Mg)固溶體。隨著保溫時間的延長，界面區(qū)寬度增加，其中Cu2Mg兩側(cè)的共晶組織區(qū)的增加更為顯著。界面區(qū)的顯微硬度明顯高于鎂合金和銅基體的顯微硬度，界面區(qū)明顯存在4個不同的硬度分布區(qū)；隨著保溫時間的延長，界面區(qū)的顯微硬度提高。
關(guān)鍵字: AZ31B/Cu 異種金屬；過渡液相擴(kuò)散焊；顯微組織；性能
（College of Materials Science and Engineering, Xi’an University of Science and Technology, Xi’an 710054, China）
Abstract:Magnesium alloy AZ31B and Cu dissimilar metals were bonded by the transient liquid-phase diffusion bonding(TLP) process. The microstructures and properties of AZ31B/Cu TLP bonded joint were researched by SEM, micro-hardness test and XRD. The results show that under the condition of 500 ℃, 40 min and 2.5 MPa, the diffusion interface zone with a width of about 450 μm forms in TLP bonded joint of AZ31B /Cu. The microstructures of AZ31B/ Cu TLP bonded joint include the grain boundary penetration layer composed of α-Mg and Mg17(Cu, Al)12 precipitated along the grain boundary of α-Mg solid solution, eutectic of α-Mg and Mg2Cu, intermetallic compound Cu2Mg,eutectic of α-Mg and Mg2Cu, and Cu(Mg) solid solution, respectively. The interfacial width increases with increasing the holding time, and the width of eutectic beside Cu2Mg layer in interface zone increases obviously. The micro-hardness of the interface zone is much higher than that of magnesium alloy and copper, and there are obvious four hardness distribution areas. The microhardness of the interface increases with increasing the holding time.
Key words: AZ31B/Cu dissimilar metals; transient liquid-phase bonding; microstructure; properties
