层间停留时间对等离子弧增材制造ER2209双相不锈钢组织及性能的影响

    Effect of Interlayer Dwell Time on Microstructure and Properties of ER2209 Duplex Stainless Steel Made By Plasma Arc Additive

    • 摘要: 研究了不同层间停留时间(1、4 min)下等离子弧增材制造ER2209堆焊试样不同平面的微观组织特征,测试了不同层间停留时间下堆焊试样x-zy-z平面在3.5wt% NaCl溶液中的极化曲线和奈奎斯特图,探究了堆焊试样不同平面的电化学腐蚀行为。结果表明:不同层间停留时间下不同平面的显微组织由铁素体相和奥氏体相组成,呈现出明显的各向异性和不均匀性,其中,在x-y平面上观察到呈近似六边形的晶界奥氏体,在x-z/y-z平面中观察到平行于z方向生长具有一定取向的奥氏体晶粒;不同层间停留时间下x-z/y-z平面的极化曲线形状大致相同,两者的Ecorr值显示出较大差异,x-z平面腐蚀速率略高于y-z平面;与x-z平面试样相比,y-z平面显示出相对较低的Qo值与相对较高的Rp值,证实了y-z平面试样上形成氧化膜的稳定性和阻隔性能的改善。层间停留时间1 min时堆焊试样具有相对较低的Ecorr值、较低的Qo值与较高的“Rp”值,与4 min相比抗腐蚀稳定性更好。

       

      Abstract: The microstructure characteristics of different planes of ER2209 surfacing samples manufactured by plasma arc additive under different interlayer dwell times (1 min, 4 min) were studied, and the polarization curves and Nyquist diagrams of the x-z and y-z planes of the surfacing samples under different interlayer dwell times in 3.5wt%NaCl solution were tested. The electrochemical corrosion behavior of the surfacing samples on different planes was investigated. The results show that the microstructure of different regions under different interlayer dwell times is composed of ferrite phase and austenite phase, showing obvious anisotropy and inhomogeneity. Approximately hexagonal grain boundary austenite is observed on the x-y plane, and austenite grains with a certain orientation are observed on the x-z/y-z plane. The polarization curves of the x-z/y-z plane are roughly same under different interlayer dwell times, and the Ecorr values of the two planes show great differences. The corrosion rate of the x-z plane is slightly higher than that of the y-z plane. Compared with the x-z plane samples, the y-z plane sample has a relatively low Qo value and a relatively high Rp value, confirming that the stability and barrier properties of the oxide film formed on the y-z plane are improved. Compared with the interlayer residence time of 4 min, the lower Ecorr value, lowerQovalue and higher Rp value under the interlayer residence time of 1 min indicate better corrosion resistance of the surfacing samples.

       

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