高强度金属材料的形变与破坏机理

项目名称： 高强度金属材料的形变与破坏机理

项目编号： No.51331007

项目类型： 重点项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 张哲峰

作者单位： 中国科学院金属研究所

项目金额： 300万元

中文摘要： 本项目主要研究典型高强度金属材料如非晶合金材料、超细晶/纳米晶材料变形与破坏机理，包括Zr和Ti基非晶合金材料及大尺寸超细晶与纳米晶铜铝合金、316L不锈钢及Fe-Mn系TWIP钢。主要研究内容包括：1）揭示剪切带对上述材料变形与断裂的作用，建立其临界失稳条件与判据；2）研究上述材料强度与韧/塑性之间的倒置关系，设计或发展高性能金属结构材料；3）研究疲劳强度与拉伸强度之间的定量关系，进而提高高强度金属材料的疲劳强度。一方面，基于各类高强度金属材料中的微观缺陷演化、剪切带与裂纹萌生、发展与失稳过程总结力学模型，提出或发展适用于各种高强度材料的破坏准则与规律，为建立高强度材料变形与破坏机理的理论基础做出贡献；另一方面，研究层错能、晶粒尺寸、应力状态与应变速率等对其力学性能的影响，进一步深入探索高强度材料的优化设计思想，为设计具有高强度可靠性使役性能的金属材料提供实验证据与理论基础。

中文关键词： 纳米晶材料;非晶合金;剪切带;断裂机制;疲劳强度

英文摘要： In this project, the deformation and fracture mechanisms of high-strength metallic materials (metallic glasses; ultrafined-grained or nanocrystalline materials) will be revealed. The materials systems will include Zr- and Ti-based bulk metallic glasses (BMGs), ultrafined-grained or nanocrstalline pure Cu and Cu-Al alloys, 316L stainless steel and Fe-Mn TWIP steel. The main scientific problems include: 1) to reveal the effects of shear bands on the deformation and fracture of metallic glasses and ultrafine-grained or nanocrystalline materials to estabalish the critical fracture criterion of the those materials. 2) To explore the trade-off relation between strength and ductility of the high-strength materials, further to design or develop adavanced strcutural materials. 3) To investigate the quantatitative relationship between fatigue strength ad tensile strength for further improving the fatigue strength of the high-strength materials in the future. Therefore, on the one hand, the initiation, propagation and critical instability of shear banding will be analyzed for the purpose of proposing suitable mechanics models. Based on the understanding on the deformation and fracture mechanisms of UFG, NC and BMG materials above, it is aimed to further develop or propose new fracture criterion for the high-strength materails in terms of the shear banding mechanisms, which will be beneficial to the optimum strategies of mechanical properties in the future. On the other hand, the effects of stacking fault energy, grain size, stress state and strain rate on the mechanial propreties will be invetaigated for better exploring the strengthening and toughening mechanisms of metallic materials. Furthermore, the optimized stratagy of high-preformace metallic materials will be proposed or developed in the future.

英文关键词： Nanocrystalline materials;Amorphous alloy;Shear band;Fracture mechanism;Fatigue strength