材料制备中的非平衡过程

NONEQUILIBRIUM PROCESSES IN MATERIALS PROCESSING

材料制备工艺中已不乏非平衡快速反应的实例、如氧气炼钢；马氏体相变处理；爆炸消除焊接应力等。近年来兴起的非平衡高新技术，如非晶、纳米晶制备中的快速冷却；自蔓燃、原位反应中的快速反应；机械合金化，超声处理中的强制反应；以及激光气相合成和微波催化过程中的诱导反应等，使材料制备科学迈向新的阶段。在进一步探讨这些非平衡过程的实质时，通过瞬态激光作用下弛豫过程的理论和实验研究，了解到微观粒子和元激发之间的能量、动量交换，及其所导致的宏观量时变关系，进而从开放体系耗散结构的自组织过程中寻求上述种种反应中的共同规律。生命过程给人们生动的启示，饮食与生长，疲劳与休息，以及损伤与愈合等启发人们在材料制备与使用过程中进行非平衡的仿生处理，如电脉冲作用下的结晶过程，疲劳过程中的电脉冲处理等的初步结果，均展示显著改善材料性能与使用寿命的诱人前景。

There are many examples of high-speed nonequilibrium reaction processes in materials processing,such as oxygen smelting; Martensitic transformation treatment; explosive relaxing of welding stress etc. The nonequilibrium high technologies are growing up recently, such as high-speed cooling in amorphous and nano-crystal processing, high-speed reactions in self-propagating high temperature sytheses and in-situ reactions; forced reactions in mechanical alloying and ultrasonic treatment, as well as laser beam induced reactions in vapor syntheses and microwave catalyzed reactions. All these processes make the processing science up to a new level. In order to further investigate the essence of nonequilibrium processes, the energy and momentum exchange between microscopic particles and excitons as well as the time dependence of related macroscopic quantities have been studied. And the common regularities of the above mentioned reactions are further studied from a viewpoint of self-organization process of dissipative structure of open system. Vivid inspiration can be enlightened by living body processes. Food and growth, fatigue and rest, as well as injuring and healing etc enlighten the way to take nonequlibrium biomimetic treatment in the process of materials processing and employment, such as the crystallization process under electropulsing and the electropulsing treatment after certain period of fatigue, these primary results show an attractive prospect of remarkable improvement of the properties and service life of materials.