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放电等离子烧结(spark plasma sintering,SPS)是最近几年国际上兴起的粉末烧结新技术,具有升温速度快、保温时间短、冷却迅速等独特优势,尤其适于纳米及非晶块体材料、陶瓷和梯度材料等先进材料的制备.然而,与利用SPS技术探索新材料制备的实验报道相比,有关其特殊烧结机制的研究极为缺乏.基此,选用导电的纯金属铜粉作为烧结原料,设计了一系列烧结实验,研究得出了SPS过程几个重要的特征烧结阶段及其中显微组织演变的规律.提出了SPS过程中烧结体显微组织演变的“自调节机制”,由此揭示了制备高致密度、均匀、细晶材料的SPS技术优势的内在机理;还对SPS烧结体的致密化过程进行了定量预测,实验测定值证实了模型预测结果.
Spark plasma sintering (SPS) is a new technology of powder sintering that has been emerging internationally in recent years. It has the unique advantages of rapid heating rate, short holding time and rapid cooling. It is especially suitable for nano and amorphous bulk materials, ceramics And gradient materials, etc. However, compared with the use of SPS technology to explore the experimental reports of new material preparation, the study on its special sintering mechanism is extremely scarce.On the basis of the selection of conductive pure copper powder as the sintering raw material, the design A series of sintering experiments have been carried out and several important characteristic sintering stages of SPS process and the rules of the microstructure evolution have been studied.The “self-adjusting mechanism” of the microstructure evolution of the sintered body during the SPS process has been proposed, The inherent mechanism of SPS technology for preparing high-density, uniform and fine-grained material was also predicted. The densification process of SPS sintered body was also quantitatively predicted. The experimental results confirmed the model predictions.