【正文】 碩士學位論文（工程碩士）2124 鋁合金固溶時效對組織和性能的影響EFFECTS OF SOLUTION AND AGING ON STRUCTURE AND PROPERTIES OF 2124 ALUMINUM ALLOY齊國棟哈爾濱工業(yè)大學2009 年 3 月國內圖書分類號： 學校代碼：10213國際圖書分類號： 密級：碩士學位論文（工程碩士）2124 鋁合金固溶時效對組織和性能的影響碩 士 研 究 生： 齊國棟導 師： 邵文柱 教授 副 導 師： 吳欣鳳 教授級高工 申請學位級別： 工程碩士學 科 、 專 業(yè)： 材料工程所 在 單 位： 東北輕合金限責任公司答 辯 日 期： 2009 年 3 月授予學位單位： 哈爾濱工業(yè)學Classified Index: School code: 10213: Secretlevel:Dissertation for the Master Degree （Master of Engineering）EFFECTS OF SOLUTION AND AGING ON STRUCTURE AND PROPERTIES OF 2124 ALUMINUM ALLOYCandidate： Qi GuodongSupervisor： Prof. Shao WenzhuAssociate Supervisor: Profengineer Wu XinfengAcademic Degree Applied for： Master of EngineeringSpecialty： Material EngineeringAffiliation: Northeast Light Alloy Co.，LtdDate of Defence： March，2009DegreeConferringInstitution： Harbin Institute of Technology哈爾濱工業(yè)大學工學碩士學位論文摘 要 采用室溫拉伸性能測試和差熱分析、金相及電子顯微分析，研究了新型 2124 合金厚板在不同熱處理制度下的拉伸力學性能、顯微組織及其變化規(guī) 律，優(yōu)化了熱處理制度；通過 MTS 試驗機測試了不同厚度新型 2124 合金 T851 狀態(tài)板材的斷裂韌性以及斷口掃描電鏡分析，研究了合金微觀組織結 構對合金板材斷裂韌性的影響。結果表明：固溶溫度和固溶時間對新型 2124 合金熱軋厚板的拉伸力學性能影響較大，合金適宜的固溶溫度為 498℃，固溶時間為 80 min。經此制度固溶處理后冷水淬火，于 185℃時效 12h，合金具有較好的強度、塑性配合。在此條件下，合金的抗拉強度 σb、 屈服強度 和延伸率 δ 分別為 466 MPa、375 MPa 和 %；適當提高固溶 溫度或延長固溶時間，合金中的過剩相的溶解程度增大，提高了合金的固溶 程度，從而提高合金的強度，但過高固溶溫度或過長固溶時間使合金的延伸 率降低。 S′過渡相是合金的主要沉淀強化相，新型 2124 合金 2%預拉伸厚 板在 170℃、185℃和 200℃下時效均具有顯著的時效強化特性，合金適宜的 時效溫度為 185℃，時效時間為 12h。在此條件下，合金的抗拉強度 σb、屈 服強度 和延伸率 δ 分別為 483 MPa、454 MPa 和 %；預拉伸變形處理 增加了合金的位錯密度，與淬火+峰時效相比，經過 2%預拉伸處理的淬火+ 預拉伸+峰時效合金 S′相分布更加彌散均勻細小，從而提高合金強度。鋁合 金板材斷裂韌性會隨著板材厚度的增加而降低，在本研究中，三個厚度板材 斷裂韌性相近似。新型 2124 合金 T851 狀態(tài)縱向斷裂韌性 40mm 厚板材最 好 ， 達 到 MPam1/2 ； 橫 向 斷 裂 韌 性 是 55mm 板 材 最 好 ， 為m1/2 ；而綜合而言 30mm 厚板材斷裂韌性最好，縱向為 MPam1/2，橫向為 MPam1/2；新型 2124 合金 T851 狀態(tài)合金板材不同 方向的斷裂韌性不同，其抗裂紋擴展能力縱向要明顯優(yōu)于橫向。關鍵詞：鋁合金；固溶和時效；預拉伸；斷裂韌性；微觀組織 I 哈爾濱工業(yè)大學工學碩士學位論文AbstractThe mechanical properties, microstructures, change law of the new 2124 thick sheet alloy at different heat treatment were investigated by room temperature tensile test, microstructures observation, electron microscopy analysis, and the heat treatment regimes were optimized。 The fracture toughness of new 2124 aluminum alloy plates of T851 state which contain different thicks were investigated using MTS. Meanwhile, the influences of the microstructure on the alloy’s fracture toughness were researched using scaning electron microscopy. The results show that: The temperature and time of solution have much effect on mechanical properties of the new 2124 thick hotrolled sheet. The suitable solution temperature and time of the alloy are 498 oC and 80 minutes respectively. At this condition, tensile strength σb, yield strength , elongation δ of the alloy is 466MPa, 375MPa, % respectively. Increasing the temperature or extending the time of solution properly can accelerate the solution of the excess phase,which can raise the degree of solution of alloy and improve the strength of alloy, but the excessive temperature or time of solution reduce the elongation of alloy. The main phase of precipitation strength of the 2124 alloy is S′phase. The alloy has strong ageing strengthening characteristic when aging at the temperature of 170 oC, 185 oC and 200 oC. The suitable ageing treatment of the alloy is ageing at 185 oC for 12h. At this condition, tensile strength, yield strength, elongation of the alloy is 483MPa, 454MPa, % respectively. Prestretching can increase the density of dislocation。 Comparing with the T6 peakaged, the T8 peakaged of prestretching treatment of 2% deformation have a more disperse, homogeneous and finer S′phase, which can increase the strength. The fatigue toughness of new 2124 aluminum alloy plates decrease with the increase of the plate thickness, but their values were approximate. Under T851 state, the longitudinal facture toughness of new 2124 aluminum alloy with 40mm thickness was best, which reached MPam1/2. the lateral facture toughness of new II 哈爾濱工業(yè)大學工學碩士學位論文2124 aluminum alloy with 55mm thickness was best, which reached MPam1/2. Comprehensively, the best facture toughness was 30mm sheet, which values were MPam1/2 of longitudinal and MPam1/2 of lateral direction respectively。 The fracture toughness of 2124T851 aluminum alloy plates is anisotropic,and the crack growth resistance in rolling direction is better than the one in transverse direction.Keywords: aluminum alloy, solution and aging, prestretching, fracture toughness, microstructure. III 哈爾濱工業(yè)大學工學碩士學位論文目錄摘要.........................................................................................................................IAbstract .......................................................................................................................II第 1 章 緒 論..............................................................................................................1國內外研究現(xiàn)狀...............................................................................................1 國外 AlCuMg 系鋁合金的研究與發(fā)展.................................................1 國內 AlCuMg 系鋁合金的研究與發(fā)展.................................................3合金元素在 AlCuMg 系合金中的作用........................................................4主合金元素................................................................................................4微量元素....................................................................................................6雜質元素.....................................................................................