本文關(guān)鍵詞： 變幅桿 超聲輔助半固態(tài)涂覆釬焊 釬縫組織 力學(xué)性能 界面行為　出處：《太原理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：在低溫條件下超聲釬焊接頭強度較低,性能較差,無法滿足工業(yè)生產(chǎn)需求的問題。因此,為了低溫釬焊更好的發(fā)展,無論是工藝優(yōu)良且接頭性能好的超聲釬焊方法,還是新型的鋁合金釬料都是亟待解決的問題。本研究從超聲釬焊裝置中變幅桿的設(shè)計出發(fā),力求設(shè)計出的釬焊裝置能夠有利于促進潤濕。繼而研究超聲參數(shù)對于釬料鋪展的影響,以期得到超聲輔助半固態(tài)涂覆釬焊試驗的最優(yōu)工藝參數(shù)。最后,使用Sn-9Zn-x Al_2O_3釬料超聲輔助半固態(tài)涂覆釬焊6061鋁合金,研究其接頭組織及力學(xué)性能。進一步研究了不同尺寸顆粒對釬焊接頭組織和性能的影響。主要的研究內(nèi)容和結(jié)果如下:首先,振幅大的變幅桿有利于釬料的鋪展。采用ANSYS有限元分析法進行變幅桿設(shè)計,最終得到變幅桿的尺寸:大端直徑為40mm,小端直徑為10.4mm,總長度為142.6mm,振幅比達到7.2。應(yīng)力集中系數(shù)比階梯型變幅桿的應(yīng)力集中系數(shù)小且易加工的圓錐過渡型變幅桿。其次,采用自行裝配的超聲釬焊裝置進行超聲涂覆試驗,確定超聲輔助半固態(tài)涂覆釬焊的最優(yōu)工藝參數(shù)。超聲變幅桿與釬料相隔30mm左右,對釬料的鋪展十分有利。當(dāng)超聲作用時間和超聲功率增加時,釬料的鋪展面積均有所變大,但不是無限變大。超聲作用時間超過4s,面積不再增加,潤濕角不再變化,處于一種穩(wěn)定狀態(tài)。當(dāng)超聲功率的數(shù)值超過350W時,面積的增加幅度減小,而厚度的減小幅度依舊維持,從而證明霧化作用對釬料有不良的影響。最終確定的超聲輔助半固態(tài)涂覆釬焊工藝參數(shù):超聲時間5s(保證其充分鋪展),超聲功率350W,溫度210℃,頻率24k Hz,壓力為3N。最后,采用Sn-9Zn,Sn-9Zn-1nm Al_2O_3和Sn-9Zn-1nm1μm Al_2O_3釬料超聲輔助半固態(tài)涂覆釬焊6061鋁合金。因納米尺寸和雙尺寸Al_2O_3顆粒的加入,提高了釬焊接頭的強度。此外,釬料中加入不同尺寸的Al_2O_3顆粒,可以不同程度地細化釬縫中的富Zn相和Sn-Zn共晶組織,提高了Al和Zn的擴散深度,但是對界面處的冶金產(chǎn)物影響不大。進而分析Sn-9Zn,Sn-9Zn-1nm Al_2O_3和Sn-9Zn-1nm1μm Al_2O_3釬料超聲輔助半固態(tài)涂覆釬焊6061鋁合金接頭斷口,Sn-9Zn接頭的斷口是脆性斷裂,而加入Al_2O_3顆粒釬料的接頭斷口都是韌性斷裂,特別是Sn-9Zn-1nm1μm Al_2O_3釬料的斷口,出現(xiàn)明顯的韌窩。并在釬縫中央發(fā)生斷裂并擴展。且其斷口組織主要是基體β-Sn相、白色細長狀的Sn-Zn共晶組織以及少量的富Zn相。通過上述的結(jié)果和分析可知,超聲輔助半固態(tài)涂覆釬焊的性能優(yōu)良,其接頭強度最少為88MPa。
[Abstract]:At low temperature, ultrasonic brazing joints have low strength and poor performance, which can not meet the demand of industrial production. Therefore, the development of low-temperature brazing is better. Both the ultrasonic brazing method with excellent technology and good joint properties and the new aluminum alloy solder are the problems to be solved urgently. This study starts from the design of the variable amplitude rod in the ultrasonic brazing device. The designed brazing device can help to promote wetting. Then the influence of ultrasonic parameters on solder spreading is studied in order to obtain the optimal technological parameters of ultrasonic assisted semi-solid coating brazing test. Finally. 6061 aluminum alloy was brazed by Sn-9Zn-x Al_2O_3 solder assisted by semi-solid coating. The microstructure and mechanical properties of brazed joints were studied. The effects of different sizes of particles on the microstructure and properties of brazed joints were further studied. The main contents and results were as follows: first of all. The ANSYS finite element analysis method is used to design the variable amplitude rod. The size of the horn is 40 mm at the big end and 10.4 mm at the small end. The total length is 142.6mm, the amplitude ratio is 7.2. The stress concentration coefficient is smaller than that of the step horn. The ultrasonic coating test was carried out by using self-assembled ultrasonic brazing device to determine the optimum technological parameters of ultrasonic assisted semi-solid coating brazing. The distance between ultrasonic horn and solder was about 30mm. When the ultrasonic action time and ultrasonic power increase, the spread area of the filler metal becomes larger, but not infinitely larger. The ultrasonic action time is more than 4 s, the area will no longer increase. The wetting angle is no longer changed and is in a stable state. When the ultrasonic power exceeds 350 W, the increase of the area decreases, while the decrease of the thickness is maintained. It is proved that the atomization has a bad effect on the solder. The final parameters of ultrasonic assisted semi-solid coating brazing are: ultrasonic time 5s (ensure its full spread, ultrasonic power 350W). The temperature is 210 鈩，

本文編號：1477974