(1. 貴州航天天馬機(jī)電科技有限公司，遵義 563000；
2. 南昌航空大學(xué) 江西省航空構(gòu)件成形與連接重點實驗室，南昌 330063；
3. 哈爾濱工業(yè)大學(xué) 先進(jìn)焊接與連接國家重點實驗室，哈爾濱 150001)
摘 要: 實現(xiàn)了20 mm厚的15% SiCp增強(qiáng)2A14鋁基復(fù)合材料攪拌摩擦對接焊，并對接頭的微觀組織和力學(xué)性能進(jìn)行了分析。結(jié)果表明：SiCp/2A14復(fù)合材料焊接接頭可以劃分為四個區(qū)域，分別是母材(BM)、熱影響區(qū)(HAZ)、熱力影響區(qū)(TMAZ)和焊核區(qū)(NZ)。其中，BM區(qū)的組織呈現(xiàn)軋制條帶狀，該組織在HAZ受熱發(fā)生了粗化；在TMAZ中，能夠觀察到由細(xì)小晶粒組成的擠壓流線狀組織；然而在NZ中，條帶狀組織消失，形成了均勻細(xì)小的等軸晶；并且NZ中SiC顆粒和白色相Al4C3得到充分細(xì)化，呈彌散均勻分布。接頭的顯微硬度最低值出現(xiàn)在HAZ和TMAZ的交界處，此處也是FSW接頭斷裂位置。接頭的抗拉強(qiáng)度、屈服強(qiáng)度和斷后伸長率分別為278 MPa、255 MPa和2.77%，分別達(dá)到母材的83.91%、77.62%和71.76%。通過數(shù)字圖像相關(guān)法(DIC)測得接頭的最大局部應(yīng)變?yōu)?6.8%。接頭的斷裂模式為韌性斷裂和脆性斷裂的混合斷裂模式。
關(guān)鍵字: 攪拌摩擦焊；鋁基復(fù)合材料；微觀組織；力學(xué)性能
（1. Guizhou Aerospace Tianma Electromechanical Technology Co., Ltd., Zunyi 563000, China;
2. Jiangxi Key Laboratory of Forming and Joining Technology for Aerospace Components, Nanchang Hangkong University, Nanchang 330063, China;
3. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China）
Abstract:FSW butt welding was attained for the 20 mm thick plates of SiCp/2A14 reinforced aluminum matrix composite with 15% in SiC volume fraction, and the microstructure and mechanical properties of the joint were analyzed. The results show that the composite welded joint can be divided into four zones, which are the base material (BM), heat-affected zone (HAZ), thermo-mechanical affected zone (TMAZ) and nugget zone (NZ). Among them, the base material microstructure presents a rolled strip organization, which is coarsened by heat in the HAZ. In the TMAZ, the extruded streamline microstructures composed of fine grains can be observed, and the strip microstructure in the NZ disappears, and a uniformly fine equiaxed grains are formed. Moreover, the SiC particles and white phase Al4C3 in the NZ are fully refined and distributed in a diffuse and uniform manner. The lowest value of microhardness of the joint is observed at the interface of the HAZ and TMAZ, which is also the place where fracture occurs. The tensile strength, yield strength and elongation of the joints are 278 MPa, 255 MPa and 2.77%, respectively, which reach 83.91%, 77.62% and 71.76% of the BM, respectively. A maximum local strain of 16.8% at fracture is observed with digital image correlation method (DIC). The joint fracture mode is a mixed fracture mode of ductile fracture and brittle fracture.
Key words: friction stir welding; aluminum matrix composite; microstructure; mechanical property
