退火孪晶对TU1薄壁无氧铜管高温处理后弯曲和腐蚀性能的影响

    Effect of Annealing Twin on Bending and Corrosion Properties of Thin-walled TU1 Oxygen-free Copper Tube after High-temperature Treatment

    • 摘要: TU1无氧铜被广泛用于烧结热管的管壳材料,经过高温烧结处理后会产生粗大的再结晶组织和织构,严重影响热管的制备以及服役性能。对未加入La和加入La的薄壁TU1铜管进行950℃高温处理,探究退火孪晶对薄壁TU1铜管弯曲及腐蚀性能的影响。结果表明,经过950℃、40 min高温处理后铜管的织构组分主要包括Goss织构,形成的Σ3晶界为退火孪晶界。添加微量的稀土La后,铜管中P含量降低,退火孪晶数量减少;铜管的抗弯强度和伸长率提高,弯曲变形能力增大;铜管的腐蚀电位向负方向移动,腐蚀电流轻微增大。3.5%的NaCl溶液浸泡测试表明铜管的腐蚀形式主要为点蚀,虽然腐蚀速率轻微增加,但是腐蚀均匀性与未加入La的相比明显提高。

       

      Abstract: TU1 oxygen-free copper is widely used as the shell material of sintered heat pipes. However, after high-temperature sintering treatment, the coarse recrystallized grains and texture were formed, which severely affected the preparation and service performance of the heat pipe. Taking the TU1 copper tubes without and with La addition as the research object, the high temperature treatment at 950 ℃ was carried out, and the effect of annealing twin on the bending performance and corrosion resistance of thin-walled TU1 copper tubes was investigated. The results show that after annealing at 950 ℃ for 40 min, the texture component of the copper tube mainly includes Goss texture, and the formed Σ3 grain boundary is annealing twin boundary. After adding a trace amount of rare earth element La, the P content of the copper tube decreases, the number of annealing twins decreases, the bending strength and elongation of the copper tube increase, the bending performance is improved, while the corrosion potential of the copper tube shifts negatively, and the corrosion current increases slightly. Immersion corrosion tests in a 3.5%NaCl solution show that the corrosion form of the copper tube is mainly pitting corrosion. Although the corrosion rate increases slightly, the corrosion uniformity is significantly improved compared with that of the tube without La addition.

       

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