极端环境下HR-2钢焊接接头的动态拉伸力学行为研究

The welded joints of HR-2 steel is one of the common structures for hydrogen storage container, which is often subject to the impact, high and low temperature during the transport and service in a hydrogen environment. However, its mechanical properties under extreme environment (hydrogen environment, high temperature, high strain rate) have not been understudied. This project aims to carry out dynamic tensile experiments under coupled elevated temperatures conditions (i.e. different oxygen content, temperature) by means of Hopkinson tensile bar system to determine the dynamic tensile properties of the welded joints of HR-2 steel at elevated temperatures. with the aid of high-speed camera, digital image correlation(DIC), and scanning electron microscopy(SEM) observation, the damage and failure mechanism, as well as the influence of hydrogen, temperature and strain rate can also be determined. Hydrogen, stain rate and temperature related constitutive model of damaged material is also constructed to provide further reference for the structural design of hydrogen storage container, and to guarantee the safety of hydrogen vehicles.

HR-2钢焊接接头是储氢容器中常见的结构，服役过程中处在氢环境下，若在运输和使用过程中若遭受冲击、高温而发生失效破坏，将会造成重大损失。而目前其在极端环境（氢环境、高温、高应变率）的力学性能及破坏机理尚不清楚。本项目采用新型带高温耦合环境（不同含氢量、不同温度）的Hopkinson拉杆系统对HR-2钢焊接接头的动态拉伸力学性能进行研究。确定氢含量对焊接接头的动态拉伸力学性能的影响，结合高速摄像、数字图像相关技术（DIC）和扫描电镜（SEM）的观察分析，明确材料的破坏机理与失效模式以及其受含氢量、温度、应变率的影响，并建立计及含氢量、温度、应变率在内的动态本构关系，为储氢容器的结构设计提供依据，并为氢能源汽车的安全提供保障。

作为储氢容器中常见结构，HR-2钢焊接接头在运输或使用过程中若遭受冲击、高温而失效破坏将会产生安全危害。深入认识其在极端环境（氢环境、高温、高应变率）的力学性能及破坏机理对于储氢容器的结构设计和安全性能具有重要意义。在本基金项目（11502259）的资助下，通过构建带高温耦合环境（不同氢含量、温度）的Hopkinson拉杆系统对HR-2钢焊接接头的动态拉伸力学性能进行测试。研究了动态加载条件下焊接接头的应变率和温度敏感性，分析了不同氢含量的氢致硬化影响。基于测试结果建立了改进的J-C本构模型，能够较好的描述计及含氢量、温度、应变率因素的焊接接头动态力学行为。通过断口微观分析并借助高速摄像、数字图像相关技术（DIC）研究了焊接接头的破坏机理。