本文關(guān)鍵詞： 高硅鋁合金 攪拌摩擦焊 脈沖激光焊　出處：《合肥工業(yè)大學》2015年碩士論文　論文類型：學位論文

【摘要】：高硅鋁合金因其密度低、線膨脹系數(shù)低、比強度高等特點,而廣泛應用于電子封裝領(lǐng)域。但是高硅鋁合金內(nèi)硅顆粒含量較多,因此其熔焊性能較差,具有較高的裂紋傾向。本文采用脈沖激光焊機針對Al-27Si進行了表面脈沖激光熔敷焊接試驗,通過調(diào)整電流、焊速、脈寬和頻率,系統(tǒng)分析各參數(shù)對焊縫成形質(zhì)量及形狀尺寸的影響規(guī)律。結(jié)果表明：提高電流、脈寬和頻率,均能增加熱輸入,增大熔深；增大焊速,焊縫熔深減小,魚鱗狀波紋寬度增大。綜合分析,在電流90A,脈寬2ms,頻率30Hz,焊速200mm/min焊接規(guī)范下,能得到成形質(zhì)量很好的焊縫。然后,采用攪拌摩擦焊接方法分別對Al-27Si、Al-50Si進行焊接試驗。研究表明,Al-27Si、Al-50Si合金FSW接頭可分為母材區(qū)、焊核區(qū)、軸肩影響區(qū)和熱機影響區(qū)四個區(qū)域。母材組織為a-Al基體和較大硅顆粒；焊核區(qū)組織為少量a-Al基體和彌散分布的細小硅顆粒；軸肩影響區(qū)內(nèi)硅比焊核區(qū)細��；熱機影響區(qū)是焊核區(qū)與母材的過渡區(qū)域,該區(qū)域硅顆粒也得到細化。旋轉(zhuǎn)速度的增加,將導致“洋蔥環(huán)”形狀明顯,細小硅的數(shù)量增多,顯微硬度增大。當轉(zhuǎn)速達到1200r/min時,焊核區(qū)顯微硬度平均值達220HVo.2,比母材高100HVo.2。分析認為Si顆粒的細化作用是顯微硬度上升的主要原因。隨焊速降低,各區(qū)域內(nèi)硅的尺寸減小。在轉(zhuǎn)速為1200r/min、焊速為50mm/min、下壓量為0.2mmm的焊接規(guī)范下,Al-27Si合金的同種焊接和Al-50Si合金的同種焊接均能實現(xiàn)良好的連接。Al-27Si與Al-50Si的異種攪拌摩擦焊接中,Al-27Si合金位于前進側(cè)時的異種攪拌摩擦焊接,焊后表面成形較好,毛刺飛邊較少。降低焊速,可有效改善焊核區(qū)及軸肩影響區(qū)組織不均勻現(xiàn)象。Al-50Si合金位于前進側(cè)時的異種攪拌摩擦焊接,焊后表面成形較差。降低焊速,不能改善焊核區(qū)及軸肩影響區(qū)組織不均勻現(xiàn)象。
[Abstract]:High silicon aluminum alloy is widely used in electronic packaging field because of its low density, low linear expansion coefficient and high specific strength. In this paper, a pulsed laser welding machine is used to test the surface pulsed laser cladding welding for Al-27Si. The welding current, welding speed, pulse width and frequency are adjusted by adjusting the current, welding speed, pulse width and frequency. The effects of various parameters on weld quality and shape and size are systematically analyzed. The results show that increasing current, pulse width and frequency can increase heat input and increase penetration depth. With the increase of welding speed, the weld penetration depth decreases and the width of fish squama ripple increases. The comprehensive analysis shows that under the welding specifications of 90A, 2ms, 30Hz, 200mm / min, the welding speed is 200 mm / min. The weld seam with good forming quality can be obtained. Then, the welding test of Al-27Si-Al-50Si is carried out by friction stir welding method. The results show that Al-27Si is welded by friction stir welding. The Al-50Si alloy FSW joint can be divided into four regions: the base metal zone, the nuke zone, the shaft-shoulder zone and the thermo-mechanical zone. The base metal structure is a-Al matrix and larger silicon particles. The microstructure of the nugget zone is a small amount of a-Al matrix and dispersed fine silicon particles. The size of silicon is smaller than that of nugget in the influence zone of shaft shoulder. The influence zone of heat engine is the transition zone between the nuke zone and the base metal, and the silicon particles in this area are also refined. The increase of rotation speed will lead to the obvious shape of "onion ring" and the increase of the amount of fine silicon. The average value of microhardness in the nugget zone is 220 HVo.2 when the rotational speed reaches 1 200 r / min. The results show that the refinement of Si particles is the main reason for the increase of microhardness. With the decrease of welding speed, the size of silicon in each region decreases, and the rotation speed is 1 200 r / min. The welding speed is 50 mm / min and the pressure is 0.2 mm. The same welding of Al-27Si alloy and the same welding of Al-50Si alloy can achieve good connection. Al-27Si and Al-50Si in dissimilar friction stir welding. When the Al-27Si alloy is located on the forward side, the surface is formed better and the burr flange is less, and the welding speed is decreased. The dissimilar friction stir welding of Al-50Si alloy located on the forward side can be effectively improved, the surface forming after welding is poor, and the welding speed is decreased. It can not improve the uneven structure of the nugget zone and the zone affected by the shaft shoulder.
【學位授予單位】：合肥工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG457.14

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