敏化温度对5083-H112双面搅拌摩擦焊接头各区晶间腐蚀性能的影响  

Effect of sensitization temperature on intergranular corrosion performance of 5083-H112 double-sided friction stir welding joint

作　　者：王松 董蕊枫 李建 孙博 李芳草 何长树 Wang Song;Dong Ruifeng;Li Jian;Sun Bo;Li Fangcao;He Changshu(National Engineering Technology Research Center,CRRC Qingdao Sifang Co.,Ltd.,Qingdao 266111,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;Key Laboratory for Anisotropy and Texture of Materials,Northeastern University,Shenyang 110819,China)

机构地区：[1]中车青岛四方机车车辆股份有限公司国家工程研究中心,山东青岛266111 [2]东北大学材料科学与工程学院,辽宁沈阳110819 [3]东北大学材料各向异性与织构教育部重点实验室,辽宁沈阳110819

出　　处：《轻金属》2022年第2期47-52,共6页Light Metals

摘　　要：本研究对5083-H112铝合金FSW接头进行了不同温度(焊态、100℃、150℃及200℃)的敏化处理,通过硝酸质量损失法(DoS)以及晶间腐蚀性能测试,研究了敏化温度对接头各区晶间腐蚀性能的影响,并结合OM、SEM和TEM等微观组织分析手段,揭示了影响接头各区晶间腐蚀性能的组织原因。研究发现:5083-H112铝合金FSW接头试样的敏化程度随敏化温度的升高呈先升高后降低的趋势,晶间腐蚀程度由高到低排序为150℃>200℃>100℃>焊态。150℃敏化处理后,接头敏化程度最大,晶间腐蚀最严重,搅拌区(NZ)的DoS值高于母材区(BM)和热影响区(HAZ)的DoS值。沿晶分布的β相特征(尺寸、数量及分布特征)是影响接头各区敏化行为和晶间腐蚀倾向性的主要因素。β相在晶界上呈薄膜状连续分布的150℃敏化处理接头的晶间腐蚀倾向性高于β相呈断续分布的200℃敏化接头。此外,各区晶内及晶界上的Al_(6)(MnFeCr)相易作为β相的形核质点,促进接头各区的敏化行为。另外,相比于晶粒尺寸粗大的BM,具有细小等轴晶组织特征的NZ在150℃敏化处理后β相沿晶分布密度较高,晶间腐蚀倾向性较高。In this study,5083-H112 aluminum alloy FSW joints were sensitized at different temperature(as-welded,100℃,150℃and 200℃).The effect of sensitization temperature on the intergranular corrosion performance of the joints was investigated by the nitric acid loss of mass(DoS)method and intergranular corrosion tests,and the reasons affecting the intergranular corrosion performance of the joints were revealed by microstructure analysis such as OM,SEM and TEM.It was found that the degree of sensitization of 5083-H112 aluminum alloy FSW joint specimens showed a trend of increasing and then decreasing along with the increase of sensitization temperature,and the degree of intergranular corrosion was ranked from high to low as 150℃>200℃>100℃>as-welded.After sensitization treatment at 150℃,the joints were sensitized to the greatest extent and intergranular corrosion was the most severe,with higher DoS value in the stirred zone(NZ)than that in the base material zone(BM)and heat-affected zone(HAZ).Theβ-phase characteristics(size,number and distribution characteristics)along the crystal distribution were the main factors influencing the sensitization behaviour and intergranular corrosion tendency in each zone of the joint.The intergranular corrosion tendency of the 150℃sensitized joints with a thin film-like continuous distribution of theβ-phase at the grain boundary was higher than that of the 200℃sensitized joints with an intermittent distribution of theβ-phase.In addition,the Al_(6)(MnFeCr)phase within the grains and on the grain boundaries of each zone tended to act as a nucleation for theβ-phase,promoting the sensitization behaviour of the joint zones.In addition,compared with BM with coarse grain size,NZ with fine equiaxed grain structure featured higherβ-phase intergranular distribution density after 150℃sensitization treatment,and higher tendency of intergranular corrosion.

关 键 词：敏化温度 晶间腐蚀性能 Β相 5083-H112铝合金 

分 类 号：TG172[金属学及工艺—金属表面处理] TG453.9[金属学及工艺—金属学]