(北京有色金屬研究總院 北京康普錫威焊料有限公司，北京 100088)
摘 要: 通過在Sn-Bi釬料中添加Cu元素制備新型Sn-30Bi-0.5Cu低溫?zé)o鉛釬料，對(duì)無鉛釬料的力學(xué)性能及微觀組織進(jìn)行分析。結(jié)果表明：Cu元素的加入抑制Bi元素在釬料/銅界面處的偏析，避免形成粗大的富Bi帶，并能夠在釬料基體中原位生成Cu-Sn金屬間化合物(Intermetallic compounds, IMC)；當(dāng)Cu含量約為0.5%(質(zhì)量分?jǐn)?shù))時(shí)，釬料的抗拉強(qiáng)度和伸長(zhǎng)率等力學(xué)性能指標(biāo)最佳，并能夠提高其抗振動(dòng)可靠性。這主要是由于在釬料基體中原位形成的棒狀或桿狀I(lǐng)MC能有效地將脆性薄弱面釘扎和在β-Sn軟相基體中形成釘軋強(qiáng)化，改善釬料的微觀組織形態(tài)，從而提高釬焊強(qiáng)度和焊點(diǎn)的抗振動(dòng)沖擊可靠性，使其性能強(qiáng)于Sn-Bi共晶的性能而接近于Sn-Bi-Ag釬料的，Sn-30Bi-0.5Cu釬料在拉伸過程中斷口存在韌性和脆性兩種混合型斷口。
關(guān)鍵字: 無鉛釬料；Sn-Bi-Cu；低熔點(diǎn)；力學(xué)性能
Sn-30Bi-0.5Cu low-temperature lead-free solder
（Beijing COMPO Solder Co. Ltd., General Research Institute for Non-ferrous Metals, Beijing 100088, China）
Abstract:A new type of low-temperature solder, Sn-30Bi-0.5Cu was fabricated by adding Cu elements into the tin-bismuth series solder. The microstructures and mechanical properties of the solder were studied. The results show that the addition of Cu elements can restrain the segregation of bismuth in the interface between solder and Cu pad, prevent the bismuth from forming into bulky crystal as strips, and in-situ form Cu-Sn intermetallic compounds(IMCs) in tin-bismuth solder. When the mass fraction of Cu is about 0.5%, both of the tensile strength and elongation reach to the best values, and the vibration reliability increases. The reason is that the addition of Cu element can improve the microstructures of the Sn-Bi-Cu solder by forming appropriate rod-like shape fine IMC crack pinning and strengthening β-Sn soft matrix, thus strengthening its soldering and vibration mechanical properties which are close to those of Sn-Bi-Ag solder and far more than those of the Sn-Bi eutectic solders. Two types of fracture occur. During the tension tests the fracture surface type of the Sn-30Bi-0.5Cu solder is a mixed fracture surface of plastic and brittle.
Key words: lead-free solder; Sn-Bi-Cu; low melting point; mechanical properties
