本文選題：快速凝固Sn-3.5Ag-0.7Cu + 激光釬焊�。� 參考：《大連理工大學(xué)》2015年碩士論文

【摘要】：傳統(tǒng)Sn-Pb釬料具有毒性,嚴(yán)重威脅著環(huán)境質(zhì)量和人體健康,因此,研究開發(fā)新的、高性能無鉛釬料勢(shì)在必行。Sn-Ag-Cu系釬料合金以其較好的綜合性能成為Sn-Pb釬料的最佳替代品,然而,其熔點(diǎn)仍相對(duì)較高。因此,利用快速凝固技術(shù)改善其性能,并對(duì)其做進(jìn)一步研究分析意義重大。本文以單輥甩帶法制備的快速凝固Sn-3.5Ag-0.7Cu釬料為研究對(duì)象,系統(tǒng)研究分析了其微觀組織、熔化特性及不同釬焊時(shí)間下界面金屬間化合物(IMC)的生長(zhǎng)行為；同時(shí)利用激光釬焊快速凝固Sn-3.5Ag-0.7Cu/Cu接頭,探求合適的激光工藝參數(shù)：最后對(duì)比分析了快速凝固和普通凝固Sn-3.5Ag-0.7Cu/Cu接頭的剪切強(qiáng)度和斷口形貌。旨在為快速凝固無鉛釬料在電子封裝領(lǐng)域的廣泛使用提供理論參考。獲得的主要結(jié)論如下：(1)與普通凝固Sn-3.5Ag-0.7Cu釬料相比,快速凝固Sn-3.5Ag-0.7Cu釬料合金的組織更均勻、熔點(diǎn)更低、熔化速度更快。(2)250℃下,短時(shí)釬焊時(shí),快速凝固Sn-3.5Ag-0.7Cu/Cu界面Cu6Sn5晶粒尺寸比普通凝固Sn-3.5Ag-0.7Cu/Cu界面處的大,并且隨釬焊時(shí)間延長(zhǎng)晶粒形貌從小面狀轉(zhuǎn)變成扇貝狀,而普通凝固Sn-3.5Ag-0.7Cu/Cu界面Cu6Sns晶粒卻在釬焊15s時(shí)才出現(xiàn)面狀；長(zhǎng)時(shí)間回流焊接時(shí),快速凝固Sn-3.5Ag-0.7Cu/Cu界面IMC厚度比普通凝固界面處的厚；快速凝固Sn-3.5Ag-0.7Cu釬料適合于低溫、短時(shí)釬焊。(3)激光功率一定時(shí),隨掃描速度降低,快速凝固Sn-3.5Ag-0.7Cu/Cu界面Cu6Sn5晶粒形貌先出現(xiàn)均勻、細(xì)小的扇貝狀,再?gòu)纳蓉悹钷D(zhuǎn)變成棱柱狀,并且隨著掃描速度降低棱柱狀Cu6Sn5晶粒尺寸增大；再次減小掃描速度時(shí),觀察到底部排列緊密,頂部有凸起的晶粒；掃描速度再次降低時(shí),界面及釬料內(nèi)部形成大板塊狀Cu6Sn5晶粒。(4)在激光功率50 w,掃描速度140 mm/min釬焊時(shí),快速凝固和普通凝固Sn-3.5Ag-0.7Cu/Cu界面IMC均呈細(xì)小扇貝狀,但前者晶粒尺寸稍大；時(shí)效時(shí),IMC尺寸隨時(shí)效時(shí)間延長(zhǎng)而變大,但普通凝固Sn-3.5Ag-0.7Cu/Cu界面IMC尺寸更大。(5)在250℃,釬焊20s、30s和50s時(shí),快速凝固Sn-3.5Ag-0.7Cu/Cu釬焊接頭剪切強(qiáng)度比普通凝固Sn-3.5Ag-0.7Cu/Cu釬焊接頭的大；而80 s時(shí),則相反；前者的剪切強(qiáng)度隨著釬焊時(shí)間增加而增加,而后者的剪切強(qiáng)度卻隨釬焊保溫時(shí)間先增加后減小。
[Abstract]:The traditional Sn-Pb solder is toxic, which is a serious threat to environmental quality and human health. Therefore, it is imperative to develop new and high performance lead-free filler metal Sn-Ag-Cu series brazing alloy as the best substitute for Sn-Pb solder with its better comprehensive properties. The melting point is still relatively high. Therefore, it is of great significance to use rapid solidification technology to improve its performance and to further study and analyze it. In this paper, the microstructure, melting characteristics and the growth behavior of intermetallic intermetallics at different brazing time were studied systematically with the rapid solidification Sn-3.5Ag-0.7Cu solder prepared by single roll strip throwing method. At the same time, the laser brazing of rapidly solidified Sn-3.5Ag-0.7Cu/Cu joints was used to find out the appropriate laser parameters. Finally, the shear strength and fracture morphology of rapidly solidified and ordinary solidified Sn-3.5Ag-0.7Cu/Cu joints were compared and analyzed. The aim is to provide a theoretical reference for the wide application of rapidly solidified lead-free solders in electronic packaging. The main conclusions obtained are as follows: compared with ordinary solidified Sn-3.5Ag-0.7Cu solder, the microstructure of rapidly solidified Sn-3.5Ag-0.7Cu brazing alloy is more uniform, the melting point is lower, and the melting rate is faster. The grain size of Cu6Sn5 at the rapidly solidified Sn-3.5Ag-0.7Cu/Cu interface is larger than that at the common solidified Sn-3.5Ag-0.7Cu/Cu interface, and with the prolonging of the brazing time, the morphology of the Cu6Sn5 grain changes from small to scalloped, while the Cu6Sns grain of the common solidified Sn-3.5Ag-0.7Cu/Cu interface appears only after 15 seconds of brazing. For long time reflux welding, the IMC thickness of rapidly solidified Sn-3.5Ag-0.7Cu/Cu interface is thicker than that of ordinary solidification interface, and the rapid solidified Sn-3.5Ag-0.7Cu solder is suitable for low temperature, short time brazing. The morphology of Cu6Sn5 grains at the rapid solidification Sn-3.5Ag-0.7Cu/Cu interface first appears uniform, fine scallop shape, then changes from scallop shape to prism shape, and increases with the decrease of scanning speed, and decreases the scanning speed again. It is observed that the bottom is tightly arranged and the top has bulge grains, and when the scanning speed decreases again, the large plate-like Cu6Sn5 grains. 4) are formed in the interface and inside of the solder. When the laser power is 50 ws, the scanning speed is 140 mm/min. The IMC of Sn-3.5Ag-0.7Cu/Cu interface of rapid solidification and ordinary solidification are both fine scallop, but the grain size of the former is slightly larger, and the size of Sn-3.5Ag-0.7Cu/Cu increases with the time of aging, but the size of IMC at the interface of ordinary solidification Sn-3.5Ag-0.7Cu/Cu is larger than that of normal solidified Sn-3.5Ag-0.7Cu/Cu at 250 鈩，

本文編號(hào)：1892345