纳米结构对奥氏体不锈钢使役性能影响的机理研究

Conventional austenitic stainless steels are widely used in industy. However, their lower fatigue limit, poor abrasion resistance and local-corrosion resistance severely limit their application in the rigour environment. In this project, synthesizing techniques and methods for preparing nanotwinned and surface gradient nanograined austenitic 304 stainless steels will be developed. The effect of both nanotwinned and the surface gradient nanograined structures on the comprehensive performance, including fatigue, abrasion and corrosion resistance, of austenitic stainless steels will be explored systematically. The fatigue properties at both high-cycle and low-cycle regimes as well as the resistance of anti-stress corrosion are expected to be improved simultaneously via reasonably tailoring the nanostructures. The relationship between the nanotwinned/gradient nanograind structures and the comprehensive performance will be clarified further. The application of nanostructured austenitic 304 stainless steels will be promoted by cooperating with Nuclear power pump industry Co., LTD, Shenyang Blower Works Group Corporation. The study would be helpful to the development of conventional industries in Liaoning province.

传统奥氏体不锈钢材料广泛应用于各工业领域，但其疲劳强度低，耐磨性和耐局部腐蚀能力不足，从而严重限制了其在苛刻工况条件下使用。本项目拟以奥氏体304不锈钢为主要研究对象，发展纳米孪晶和梯度纳米结构不锈钢材料的制备技术及相关方法。系统研究纳米孪晶与表面梯度纳米结构对奥氏体不锈钢疲劳行为、磨损及耐腐蚀性能的影响规律。通过纳米结构设计和调控，实现奥氏体不锈钢高、低周疲劳性能及抗应力腐蚀能力的同步提高，深入理解其结构性能关系，探索纳米结构工程合金的疲劳、磨损及腐蚀机制。并联合沈阳鼓风机集团核电泵业有限公司共同推进纳米结构不锈钢的应用，为辽宁省支柱产业向高技术转型提供有力支持。

针对传统粗晶奥氏体不锈钢疲劳强度低，寿命短、抗氢脆及耐腐蚀能力差等使役性能不足的现状，本项目紧密围绕通过设计和调控奥氏体304不锈钢等金属材料的微观组织结构来提高材料的综合服役性能展开研究。发展了纳米孪晶和梯度纳米结构不锈钢材料的制备技术及相关方法；系统研究了纳米孪晶及梯度纳米结构对奥氏体不锈钢的拉伸、疲劳、断裂、氢脆及腐蚀行为的影响规律；建立了纳米结构与性能（拉伸、疲劳及断裂等）的内在对应关系，通过纳米孪晶及梯度纳米结构实现了奥氏体不锈钢高、低周疲劳性能、断裂韧性、抗氢脆及耐腐蚀能力的同步提高，提出优化金属综合使役性能的多尺度结构构筑原理。此外，发现了纳米孪晶金属与循环历史无关的独特循环稳定响应，为发展下一代抗疲劳损伤结构材料奠定了基础。本研究成果有力增强了辽宁在传统工业材料性能优化方面的自主创新能力，为向高端装备制造产业升级提供技术支撑，并成功将梯度纳米结构设计应用于沈鼓公司的零部件中。