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烧结过程可改进压制-烧结的铁基材料的物理-力学性能。烧结时因扩散产生颗粒结合与合金化;随着烧结时间增长,强化材料性能。烧结的作用通过显微组织特征(诸如颗粒边界与孔隙边缘)的变化可以看出。烧结的一些改进表现为颗粒边界消失,孔隙边缘变得较平滑和颗粒间尖角特征数量减少。一般将这些特征与特性的外观和它们发生的频率一起当做是烧结程度。用众所周知的体视技术(Stereological practies)与适当制备的金相试样,可以判定烧结程度。关于判定与区分烧结程度不同的材料,将讨论3种试验方法。另外,将用烧结时间不同的铁-铜-碳预混合粉材料的图像来说明这些显微组织的变化。
The sintering process can improve the physico-mechanical properties of pressed-sintered iron-based materials. Sintering due to the proliferation of particle binding and alloying; with the sintering time increases, strengthening the material properties. The effect of sintering can be seen by the changes in the microstructure features such as grain boundaries and pore edges. Some improvements in sintering appear as the disappearance of the grain boundaries, the smoothening of the pore edges and the reduction in the number of sharp-pointed features between the grains. The appearance of these features and properties as well as the frequency with which they occur are generally considered to be degrees of sintering. The degree of sintering can be determined using the well-known Stereological Practices and suitably prepared metallographic samples. Three different test methods will be discussed regarding the determination of materials that distinguish between different degrees of sintering. In addition, changes in these microstructures will be illustrated by images of iron-copper-carbon premix powders with different sintering times.