热等静压成型温度对雾化合金粉制备的9Cr-ODS合金钢组织及拉伸性能的影响

Effect of hot isostatic pressing temperature on microstructure and tensile properties of 9Cr-ODS alloy steel prepared from atomized alloy powders

以雾化合金粉为原料采用热等静压成型制备了9Cr-ODS合金钢。首先,使用扫描电镜(SEM)和能谱仪(EDS)分析了雾化法制备的合金粉的表面形貌和化学成分。利用电子背散射衍射(EBSD)、透射电镜(TEM)、小角X射线散射(SAXS)等研究了9Cr-ODS合金钢的晶粒形貌及平均尺寸、析出相的形貌及分布密度。结果表明:随着热等静压温度的升高,9Cr-ODS合金钢样品的晶粒逐渐长大,抗拉强度逐渐降低;900℃成型制备的9Cr-ODS合金钢的平均晶粒尺寸为0.62μm,其强度高于其他两个成型温度制备的样品。9Cr-ODS合金钢中各类型析出相的分布密度随着成型温度的升高而降低,尺寸则呈现长大的趋势。测试温度越高样品的抗拉强度越低,700℃测量时3个样品的抗拉强度比较接近。测试温度的升高会使样品的伸长率升高,但900℃成型制备的样品的伸长率在700℃测量时出现下降的现象。

9Cr-ODS alloy steel was prepared by hot isostatic pressing(HIP)with atomized alloy powders as raw material.Firstly,the surface morphology and chemical composition of the atomized alloy powders were analyzed by scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS).The morphology and average size of grain and morphology and distribution density of precipitates of the 9Cr-ODS alloy steel were studied by means of electron backscatter diffraction(EBSD)technique,transmission electron microscopy(TEM)and small angle X-ray scattering(SAXS).The results show that with the increase of hot isostatic pressing temperature,the grain size of the 9Cr-ODS alloy steel gradually grows and the tensile strength gradually decreases.The average grain size of the 9Cr-ODS alloy steel prepared by HIP at 900℃is 0.62μm,and its strength is higher than that of the samples prepared at the other two HIP temperatures.The distribution density of various precipitates in the 9Cr-ODS alloy steel decreases with the increase of HIP temperature,while the size tends to grow.The higher the test temperature is,the lower the tensile strength of the sample is.The tensile strength of the three samples is close when measured at 700℃.The increase of test temperature will increase the elongation of the sample,but the elongation of the sample prepared by HIP at 900℃will decrease when measured at 700℃.