發(fā)布時間：2018-06-26 21:22

  本文選題：錫基釬料 + 韌-脆轉(zhuǎn)變　； 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：在空間探索與航天應(yīng)用中,航天器中的一些電子器件和設(shè)備不得不面臨艙外環(huán)境,如極低溫、大溫差等。電子電路的焊點(diǎn)是對熱、力環(huán)境最為敏感的部位;焊點(diǎn)在極限環(huán)境下力學(xué)性能發(fā)生極大的改變、遭受損傷,導(dǎo)致失效。因此研究電子元器件互連材料在極低溫環(huán)境下的力學(xué)性能及失效模式便十分重要。目前,最常用的電子互連的連接材料為錫基釬料,且研究表明錫基釬料在低溫下會發(fā)生斷裂模式由韌性斷裂向脆性斷裂的轉(zhuǎn)變,另外Ag元素的加入會對失效溫度及模式產(chǎn)生較大影響。因此本課題旨在研究錫基釬料的低溫脆斷機(jī)理。選擇純錫及99.3Sn0.7Cu、96.5Sn3Ag0.5Cu、62Sn36Pb2Ag、63Sn37Pb、10Sn90Pb等5種錫基釬料作為研究對象,在150J的沖擊能量、5.24m/s的沖擊速度下,在20~-150℃的溫度區(qū)間內(nèi)進(jìn)行了夏比沖擊實(shí)驗(yàn)。完成沖擊實(shí)驗(yàn)后通過觀察各種釬料的沖擊曲線及宏觀斷口上韌性-脆性斷裂區(qū)域的比例,得到所研究各種釬料的韌-脆轉(zhuǎn)變溫度。在掃描電子顯微鏡(SEM)下觀察不同釬料不同溫度下的斷口微觀組織,使用能譜儀分析所觀察到的第二相的成分,最后得出純錫及錫基釬料不同溫度下的斷裂機(jī)理。研究表明,純錫的韌脆轉(zhuǎn)變溫度在-50℃左右。在20~-40℃內(nèi)斷口為大面積的纖維區(qū);從-50℃開始,出現(xiàn)了冰糖狀沿晶斷裂的斷口形貌,并在局部有穿晶解理斷裂的形貌。在錫基釬料中,Cu元素的加入使得99.3Sn0.7Cu釬料的斷裂韌性略有上升,但韌-脆轉(zhuǎn)變溫度基本不變;與基體生成了纖維狀第二相Cu6Sn5,促使斷裂模式為穿晶解理斷裂。加入Ag元素后,96.5Sn3Ag0.5Cu釬料的韌脆轉(zhuǎn)變溫度升高至-40℃,且觀察到了枝狀及纖維狀的Ag3Sn第二相,斷裂模式為解理斷裂。由于Pb元素的加入,62Sn36Pb2Ag釬料的韌脆轉(zhuǎn)變溫度區(qū)間很寬,韌脆轉(zhuǎn)變的發(fā)生也較為平緩,韌-脆轉(zhuǎn)變溫度為-50℃,斷裂模式為準(zhǔn)解理斷裂,在小平面的撕裂棱附近觀察到了Ag3Sn顆粒,其作為裂紋源促進(jìn)了斷裂的發(fā)生。63Sn37Pb釬料基本沒有發(fā)生韌脆轉(zhuǎn)變,斷口形貌主要以韌窩為主,局部觀察到了脆性斷裂形貌。當(dāng)Pb元素含量上升至一定程度,10Sn90Pb釬料一直為韌性斷裂,其中含有富錫相作為第二相質(zhì)點(diǎn)促進(jìn)微孔集聚型斷裂的發(fā)生。
[Abstract]:In space exploration and space applications, some electronic devices and equipments in spacecraft have to face the extravehicular environment, such as very low temperature, large temperature difference and so on. The solder joint of electronic circuit is the most sensitive to the thermal and force environment, and the mechanical properties of the solder joint change greatly under the limit environment, which results in the failure of the solder joint. Therefore, it is very important to study the mechanical properties and failure modes of electronic component interconnection materials at very low temperature. At present, the most commonly used bonding material for electronic interconnection is tin solder, and it is shown that the fracture mode of tin based solder will change from ductile fracture to brittle fracture at low temperature. In addition, the addition of Ag element will have a great effect on the failure temperature and mode. Therefore, the purpose of this paper is to study the brittle fracture mechanism of tin-based solders at low temperature. Five kinds of tin based solders, such as pure tin and 99.3Sn0.7CuO96.5Sn3Ag0.5CuCU 62Sn36Pb2Agn63Sn37Pbt10Sn90Pb, were selected as the objects of study. Charpy impact tests were carried out at the temperature range of 20 鈩，

本文編號：2071440