本文選題：7A52鋁合金 + 光纖激光焊　； 參考：《內(nèi)蒙古工業(yè)大學(xué)》2017年碩士論文

【摘要】：7A52鋁合金是中國自行研發(fā)生產(chǎn)的高強(qiáng)裝甲鋁合金,在實際工程應(yīng)用中通常以焊接結(jié)構(gòu)的形式而存在。但是在以往的焊接過程中焊接氣孔、焊縫強(qiáng)度低等問題嚴(yán)重影響了接頭的使用性能,激光焊接技術(shù)的快速發(fā)展則有望解決這些焊接問題。采用光纖激光器,以6mm厚7A52鋁合金為研究對象,對其進(jìn)行焊接,接頭形式為對接。以接頭抗拉強(qiáng)度為評價指標(biāo),采用正交試驗方法系統(tǒng)地研究了焊接速度、焊接功率和離焦量對接頭抗拉強(qiáng)度的影響程度,運(yùn)用極差分析手段確定了較優(yōu)焊接參數(shù)組合。焊接參數(shù)對接頭抗拉強(qiáng)度的影響程度順序為:RcRaRb,并得到了6mm厚7A52鋁合金光纖激光焊較優(yōu)參數(shù)組合:焊接功率5.2kW、焊接速度40mm/s、離焦量為0mm,此參數(shù)下的接頭抗拉強(qiáng)度為336MPa,接頭系數(shù)為69.7%,斷裂類型屬于韌脆混合斷裂。在120℃、140℃和160℃三種時效溫度下,分別對焊接接頭進(jìn)行了單級時效研究,發(fā)現(xiàn)母材與焊縫的硬化曲線變化規(guī)律基本一致;時效溫度對接頭時效硬化過程的影響相當(dāng)顯著,隨時效溫度的升高,焊接接頭的顯微硬度變化更加明顯,達(dá)到峰值時效硬度的時間明顯縮短;當(dāng)時效溫度140℃、時效時間16h時,能夠獲得綜合性能更好的焊接接頭;在單級時效過程中起主要強(qiáng)化作用的是MgZn2相,在峰時效狀態(tài)下的主要強(qiáng)化相是細(xì)小的η,相和GP區(qū)。
[Abstract]:7A52 aluminum alloy is a kind of high strength armored aluminum alloy which is developed and produced by China. It usually exists in the form of welded structure in practical engineering application. However, in the past welding process, such problems as welding porosity and low weld strength have seriously affected the performance of the joint, and the rapid development of laser welding technology is expected to solve these welding problems. The 6mm thick 7A52 aluminum alloy was welded by fiber laser. The influence of welding speed, welding power and defocus on the tensile strength of joints was studied systematically by orthogonal test. The optimum welding parameters were determined by means of range analysis. The influence of welding parameters on the tensile strength of the joint is in the order of: Rc RaRb. The optimum parameters of 6mm thick 7A52 aluminum alloy fiber laser welding are obtained: welding power 5.2 kW, welding speed 40 mm / s, defocus 0 mm. The tensile strength of the joint under this parameter is 336 MPA. The joint coefficient is 69.7 and the fracture type belongs to ductile and brittle mixed fracture. The single stage aging of welded joints at 120 鈩，

本文編號：1825989