(鄭州機(jī)械研究所 新型釬焊材料與技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，鄭州 450001)
摘 要: 為了研究釬料元素Al+Zn對(duì)鎂合金釬焊接頭顯微組織與抗剪強(qiáng)度的影響，以兩種Al-Mg-Zn鎂合金釬料對(duì)變形鎂合金AZ31B進(jìn)行了高頻感應(yīng)釬焊，研究?jī)煞NAl-Mg-Zn鎂合金釬料的顯微組織、釬焊接頭的顯微組織及力學(xué)性能。結(jié)果表明：隨著釬料中Al+Zn元素含量(質(zhì)量分?jǐn)?shù))的增加，釬料的固相線和液相線溫度也隨之增加；在釬焊過(guò)程中兩種Al-Mg-Zn鎂合金釬料與母材AZ31B均發(fā)生強(qiáng)烈合金化作用，在釬縫中均生成α-Mg+ β-Mg17(Al,Zn)12離異共晶組織，釬料的原始顯微組織消失，且隨著釬料中Al+Zn元素含量的增加，釬焊接頭中的金屬間化合物相β-Mg17(Al,Zn)12的體積分?jǐn)?shù)和顯微硬度也隨之增加，同時(shí)釬焊接頭力學(xué)性能隨之降低。釬焊接頭的斷裂形式均為沿晶脆性斷裂，斷裂均產(chǎn)生在金屬間化合物相β-Mg17(Al,Zn)12處。
關(guān)鍵字: 鎂合金；釬料；釬焊；離異共晶組織；抗剪強(qiáng)度
（State Key Laboratory of Advanced Brazing Filler Metals and Technology,
Zhengzhou Research Institute of Mechanical Engineering, Zhengzhou 450001）
Abstract:In order to research effect of Al+Zn elements of the filler metal on microstructures and mechanical properties of magnesium alloy brazed joint, the wrought magnesium alloy AZ31B was joined using two kinds of Al-Mg-Zn filler metals by high-frequency induction brazing mode. The microscopic structure of the filler metal, microscopic structure and the mechanical properties of the brazed joint were studied. The results show that the solidus and liquidus temperatures of the filler metals are light increment when the contents of Al+Zn elements of the filler metals increase. The α-Mg+β-Mg17(Al,Zn)12 divorced eutectoid structure forms in the brazing region due to the intensive alloying between the molten two kinds of Al-Mg-Zn filler metals and the solid base metal AZ31B occurred in the brazing process. The original microscopic structure of the filler metals disappears completely after the brazing process. As contents of Al+Zn elements of the filler metal increase, the volume fraction and microhardness of intermetallic compound β-Mg17(Al,Zn)12 increase too, and the shear strength of the brazed joints decreases. The overlapped joints exhibit intergranular fracture mode, the fracture comes from β-Mg17(Al,Zn)12 hard brittle phase.
Key words: magnesium alloy; filler metal; brazing; divorced eutectic; shear strength
