高温条件下材料与结构力学行为的研究进展

RECENT PROGRESS IN HIGH TEMPERATURE MECHANICAL BEHAVIOR OF MATERIALS AND STRUCTURES

本文回顾了最近十年来材料与结构高温力学行为若干热点问题的研究进展,包括高温下材料力学行为的多尺度特性、多组元材料的蠕变力学性能、拘束条件下的高温断裂理论、高温下的结构安全评定理论等.指出:为了保障重大高温装备的安全运行,并为高技术工艺装备的实现提供理论支撑,必须实现时间尺度与空间尺度上的事件的转换与关联,解决高温材料老化的物理化学动力学问题,理清应力应变场与化学动力学过程的相互作用;应强化材料界面缺陷及高温结合强度的微观测量方法与理论分析的研究;需要进一步研究损伤影响下的实际蠕变裂尖应力场,精确描述拘束效应的蠕变裂纹扩展速率模型,以进一步建立拘束下的高温断裂理论;在高温结构的安全评定方面,在目前的失效评定图基础上引入与材料、结构同时关联的损伤维度(时间相关),可望实现较为复杂损伤机制下的失效评定.

The paper reviews a decade of progress in high temperature mechanical behavior of materials and structures. The highlighted topics are multiscaling of mechanical behavior of materials at high temperature, creep mechanics of multi- component materials system, high temperature fracture under constraint and safety assessment of high temperature components. To meet the future challenges of the safe operation of high temperature plants and the development of high-tech machines, more efforts should be taken to address some critical issues, which includes correlation and transformation of the events in temporal and spatial scales： to understand the physico-ehemical kinetics and the influence of external stresses; the measurement and theoretical interpretation of interfaeial strength and defects at high temperature; the development of high temperature theory that takes into account the constraint effect on the stress field ahead of crack tip and creep crack growth rate; the extension of the current failure assessment diagram to cover the complexity of damage mechanisms by introducing a time-dependent damage scale.