( 蘭州理工大學 甘肅省有色金屬新材料國家重點實驗室，
蘭州 730050)
摘 要: 對10 mm厚LF2鋁合金攪拌摩擦焊接進行了研究。 結(jié)果表明：焊接厚板時，為防止出現(xiàn)隧道型缺陷，須在較低的焊速和轉(zhuǎn)速下進行。當焊速為9 mm/min，轉(zhuǎn)速為950 r/min，焊接輸入能量為6 230 W時，接頭強度值最高，其值與母材強度值相等。接頭處由平均尺寸約為15 μm的均勻細小的晶粒組成；熱影響區(qū)平均晶粒尺寸較大，其最大值約為28 μm；熱機械影響區(qū)內(nèi)組織細長，局部區(qū)域最大長度可達到85 μm。焊核區(qū)平均硬度與母材相當，中心最高硬度可達HV95，近縫區(qū)硬度低于母材硬度。
關(guān)鍵字: 攪拌摩擦焊； 鋁合金； 接頭； 微觀組織； 焊接參數(shù)； 晶粒
（ State Key Laboratory of Advanced Non-ferrous Metal Materials, Gansu Province,
Lanzhou University of Technology，
Lanzhou 730050，China）
Abstract: The welding of 10 mm thick LF2 aluminum alloy in friction stir welding was investigated. The results show that thicker plate should be jointed at lower welding velocity and rotation speed, otherwise there would get the joint with huge tunnel defect. The highest strength joints that are equal to parent metal can be obtained at 9 mm/min of welding velocity, 950 r/min of rotational speed and 6 230 W of input energy, which are regarded as the most ideal parameters under experimental welding conditions. There are the smallest size grains of 15 μm in weld nugget; Heat affected zone are composed of coarse grains and the largest size of heat affected zone microstructure is 28 μm; Thermomechanically affected zone consists of stripy structure which is 85 μm in length in some area. Average microhardness in weld nugget is equal to parent metal’s, the most microhardness is HV95 and lower than parent metal’s in the area near weld nugget .
Key words: friction stir welding；aluminum alloy；joint；microstructure；welding parameters; grain
