(江蘇大學(xué) 先進(jìn)制造與現(xiàn)代裝備技術(shù)工程研究院，鎮(zhèn)江 212013)
摘 要: 采用金相顯微鏡、掃描電鏡、常溫拉伸及斷裂韌性測(cè)試等實(shí)驗(yàn)方法研究2099鋁鋰合金擠壓材的組織和力學(xué)性能。結(jié)果表明：合金在T83時(shí)效處理中采用(121 ℃, 14 h)一級(jí)時(shí)效和(181 ℃, 30~66 h)二級(jí)時(shí)效時(shí)，其屈服強(qiáng)度隨二級(jí)時(shí)效時(shí)間的延長(zhǎng)而顯著提高，二級(jí)時(shí)效時(shí)間為48和66 h時(shí)的屈服強(qiáng)度為445和491 MPa，抗拉強(qiáng)度為543和551 MPa，伸長(zhǎng)率為5.7%和4.7%，合金彈性模量高達(dá)78.75 GPa，實(shí)測(cè)密度為2 517 kg/m3，具有極高的比強(qiáng)度和比剛度。在雙級(jí)時(shí)效制度為(121 ℃, 14 h)+(181 ℃, 48 h)時(shí)，合金斷裂韌性KIC值為22.87 MPa×m1/2，斷裂裂紋沿著細(xì)小再結(jié)晶組織、粗大不(難)溶第二相等組織缺陷擴(kuò)展。
關(guān)鍵字: 2099鋁鋰合金擠壓材；時(shí)效制度；組織；力學(xué)性能
（Engineering Institute of Advanced Manufacturing and Modern Equipment Technology,
Jiangsu University, Zhenjiang 212013, China）
Abstract:The microstructure and mechanical properties of 2099 Al-Li alloy extrusion materials were investigated by optical microscopy (OM), scanning electron microscopy (SEM), ambient temperature tensile testing and fracture toughness testing, and so on. The results show that, when the alloy is aged at T83 heat treatment which includes the first aging treatment (121 ℃, 14 h) and the secondary aging treatment (181 ℃, 30~66 h), the yield strength improves significantly with the increase of the secondary aging time. The yield strength, tensile strength and elongation are 445 and 491 MPa, 543 and 551 MPa and 5.7% and 4.7%, respectively, at the secondary aging time of 48 and 66 h. The elastic modulus is as high as 78.75 GPa and actual density is 2 517 kg/m3. The alloy has superior specific strength and specific stiffness. When the duplex aging is (121 ℃, 14 h)+(181 ℃, 48 h), the fracture toughness KIC value of alloy is 22.87 MPa×m1/2. The crack expands along the microstructure defects, such as the fine recrystallization structure, the coarse insoluble second phase, and so on.
Key words: 2099 Al-Li alloy extrusion materials; aging treatment; microstructure; mechanical properties
