【正文】 only cost savings, but also one of effective measures to reduce the plexity of the technology. Based on the AZ31 and AZ61 magnesium alloy as the research object, through the welding parameters under different process adjustment, and bined with the microstructure analysis and mechanical properties testing, a systematic study of the different welding speed and the welding line energy effect of microstructure and mechanical properties of joint of magnesium alloy laser welding and TIG, clarification the relationship between the microstructure evolution and mechanical properties of the welded joint。鎢極氬弧焊。 關(guān)鍵詞：鎂合金。隨著焊接線能量在AZ31鎂合金激光焊接熔合區(qū)，呈現(xiàn)胞狀晶→胞狀樹枝晶→樹枝晶→等軸晶的轉(zhuǎn)變。 較小功率的前提下，AZ31鎂合金激光焊接熔深增加線能量增加。的實驗事實的基礎(chǔ)上的理論分析，得出以下結(jié)論： 間增加的能量不僅會導(dǎo)致增加的TIG焊接接頭的AZ31鎂合金熱影響區(qū)，熱影響區(qū)和熔合區(qū)的晶粒粗化，連續(xù)減少β相的熱影響區(qū)和熔合區(qū)的顆粒或不連續(xù)β相增加。在本文中，AZ31和AZ61變形鎂合金的研究，通過調(diào)整不同的焊接工藝，金相組織分析和力學(xué)性能測試，系統(tǒng)的研究，不同的鎂合金激光焊接和TIG焊接熱輸入量和焊接速度焊接參數(shù)接頭的組織和力學(xué)性能的影響，闡明組織演變，并獲得焊接接頭的力學(xué)性能之間的關(guān)系。這些屬性導(dǎo)致生產(chǎn)困難和昂貴的方法制備的鎂合金部件的結(jié)構(gòu)復(fù)雜。摘 要鎂合金具有密度低，強度高，導(dǎo)熱性能好，抗震性能好，電磁屏蔽性能優(yōu)勢以及應(yīng)用在汽車，航空航天，電子信息產(chǎn)業(yè)，有廣闊的發(fā)展前景。然而，在室溫下，用緊密堆積的六方晶系結(jié)構(gòu)的鎂，滑系統(tǒng)，塑性變形。因此，使用鎂合金結(jié)構(gòu)簡單焊接方法連接成一個復(fù)雜的結(jié)構(gòu)，在鎂合金結(jié)構(gòu)件制造，不僅節(jié)省成本，而且還減少過程的復(fù)雜性的有效措施之一。強化機理模型預(yù)測了鎂合金的高功率激光焊接接頭的屈服強度增強機制。然而，如果該行的能量太低，將導(dǎo)致在焊縫中的未焊透和孔隙度，從而降低了在焊接接頭的拉伸強度。焊縫的表面上的等離子體有利于激光焊縫的深度增加。此外，適度的提高線能量可以降低鎂合金的激光焊接頭的應(yīng)變速率，降低焊接凝固裂紋的形成的概率。激光焊。微觀組織。 and the strengthening mechanism model to forecast the yield strength enhancement mechanism of high power laser welding of magnesium alloy joints. Based on the experimental facts, bined with theoretical analysis, the main conclusions are the following:1, line energy not only leads to AZ61 magnesium alloy gas tungsten arc welding HAZ width increases, heat affected zone and Fusion Zone grain coarsening, and make continuous β heat affected zone and fusion zone of reduced and granular or discontinuous beta phase increased. Low line energy will lead to lack of penetration and porosity in weld appearance, and the ultimate tensile strength of the welded joint reduction2, in the condition of low power, AZ61 wrought magnesium alloy laser weld penetration increases with the increase of welding line energy. Plasma welding on the surface of thin and stable in favor of laser weld penetration increase. With the increase of welding line energy, influenced by constitutional undercooling degree of change,the fusion zoneof AZ61 magnesium alloy laser welding deformation, microstructure evolution of the critical region near the partially melted zone are presented in the cellular crystal and cellular dendrite, dendritic, equiaxed grains. In addition, appropriately increasing the line energy can reduce the magnesium alloy laser welding joint strain rate, thereby reducing the possibility of the formation of weld solidification cracks in the line, but the high energy will lead to weld HAZ liquation crack increase. Keywords : magnesium alloy。 TIG welding。 mechanical properties33 / 38目 錄中文摘要.....................................................................................................................................I英文摘要....................................................................................................................................II第1章 緒論.................................................................................................................................1 鎂合金得簡介 ................................................................................................................1 鎂合金得發(fā)展...........................................................................................................1 鎂合金得分類...........................................................................................................2 鎂合金焊接得國內(nèi)外研究現(xiàn)狀 ....................................................................................2 本文得主要研究內(nèi)容 ....................................................................................................6第2章 研究內(nèi)容與方法 ...........................................................................................................7 實驗材料 ........................................................................................................................7 焊接設(shè)備 ........................................................................................................................7 交流鎢極氬弧焊焊機...............................................................................................7 小功率激光脈沖焊接機 .........................................................................................8 大功率激光器...........................................................................................................8 性能檢測設(shè)備 ................................................................................................................8 焊接接頭試樣得制備...............................................................................................8 掃描電子顯