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Zr-Sn-Nb-Cr-Fe锆合金搅拌摩擦焊工艺及焊缝组织和性能

Friction stir welding process microstructure and property of weld for Zr-Sn-Nb-Cr-Fe zirconium alloys

  • 摘要: 文中对Zr-Sn-Nb-Cr-Fe锆合金搅拌摩擦焊(friction stir welding,FSW)工艺、微观组织和腐蚀性能进行了分析. 结果表明,采用W-25%Re的搅拌工具在转速250 r/min、焊接速度40 mm/min、顶锻压力10 kN、氩气保护条件下可以获得成形良好且无焊接缺陷的锆合金FSW接头. 搅拌区(stir zone,SZ)剧烈的塑性变形促进动态再结晶、合金元素扩散和晶粒细化,晶粒尺寸随着转速增加而增大,同时SZ内在晶界位置处析出大量的形状不规则的第二相粒子. 不同焊接参数制备的FSW接头在360 ℃、18.6 MPa中性水中腐蚀72 h后均表现为黑色、光亮、致密的氧化膜,但随着转速增加接头耐腐蚀性能降低.

     

    Abstract: Process performance, microstructure and corrosion properties of friction stir welded (FSW) joints of Zr-Sn-Nb-Cr-Fe zirconium alloys were studied in the present paper. The results indicate that the recommended zirconium alloys FSW joints with good shape and no welding defects were obtained by W-25%Re stir tool under the conditions of 250 rpm rotational speed, 40 mm/min welding speed, 10 kN axial force and argon protection. In stir zone (SZ), the severe plastic deformation leads to dynamic recrystallization, diffusion of alloying element and grain refinement and grain size increases with the increase of rotational speed. As the same time, a large number of irregularly shaped second phase particles were precipitated at the grain boundaries. These FSW joints prepared by different welding parameters exhibited black, bright and dense oxide film after being corroded in neutral water at 360 ℃, 18.6 MPa for 72 hours. However, the corrosion resistance of FSW joints decreases with the increase of rotational speed.

     

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