聚龙一号装置上钽在准等熵压加载下的强度特性研究

Metal strength research under extreme conditions is an important application for weapons physics and aeromechanics. Material’s response has an affinity with microstructure, load path, pressure and temperature, etc. Magnetically driven isentropic compression as a new experimental technique between quasi-static and impact, has low increased entropy and temperature. Magnetic pressure produced from the current flow in the load electrode compress the sample, which is decided by the load current shape and load configuration. PTS facility includes 24 modules, which help it can control the load current shape in a relative width range, thereby provided a different strain rates isentropic compression experimental platform for millimeter thick and centimeter diameter samples. Tantalum as an typical high-Z and BCC crystal metal, it’s strength characterization research is representative of dynamic metal material properties under extreme conditions, which growing to be an emphasis research topic. In this work, based on the output characteristic of PTS facility, we can control the sample load path via shaping the load current, thereby analysis different type tantalum strength properties with experimental measure and micro simulation. This research will complement the low temperature, high strain rate, high pressure strength data of tantalum, comparing with the quasi-static and shock impact data, can verification of the strength model for tantalum. In addition, the work will develop our relativity experimental techniques, simulation and analysis ability, and accomplish fundamental experimental techniques and theoretic work of dynamic material properties experiments using pulsed magnetic compression.

金属材料在极端条件下的强度研究与微结构、加载路径、压力、温度等密切相关，在武器物理、航天航空等领域有着重要应用。磁驱动准等熵加载通过电流产生的磁压力加载材料，加载路径由负载电流波形和负载结构决定。作为介于静高压加载和冲击加载的新型实验技术，熵增小、温升低。聚龙一号（PTS）装置包括24电流支路，可在较大范围内控制负载电流波形，从而实现毫米厚厘米直径样品在不同应变率历史下的准等熵加载。钽是一种典型的高Z体心立方（BCC）金属，可作为标准材料开展BCC金属在极端加载条件下的强度特性研究。本研究将基于PTS装置，通过调节负载电流波形实现样品加载路径控制，在一定压力-应变率范围，开展不同工艺钽样品强度特性的实验与模拟分析研究。研究可补充国内钽的低温高压高应变率下的强度数据，用于校验现有的强度模型。从而发展钽强度特性实验技术与模拟分析能力，为开展更多材料的动力学特性研究奠定了实验和理论基础。

金属材料在极端条件下的强度研究与微结构、加载路径、压力、温度等密切相关，在武器物理、航天航空等领域有着重要应用。磁驱动准等熵加载通过电流产生的磁压力加载材料，加载路径由负载电流波形和负载结构决定。作为介于静高压加载和冲击加载的新型实验技术，熵增小、温升低。本研究基于聚龙一号（PTS）装置输出特性，发展了包含负载结构优化、电极及样品尺寸设计、电流波形设计与实现、预估模拟分析和波剖面诊断与数据处理等5个方面的磁驱动准等熵加载实验技术，形成了针对强度实验的加载路径控制技术，样品的加载压力峰值超过150 GPa，加载应变率范围10^4 s^-1~10^7 s^-1（平均应变率10^5-6 s^-1）。成功获取了不同工艺钽样品在峰值压力29-161 GPa，平均加载应变率4-9×10^5 s^-1准等熵加载下的强度特性数据，对退火/未退火钽的准等熵压缩强度特性形成了规律性认识，验证了金属Ta在10^5-6 s^-1应变率的强度基本符合SG强度模型。形成的材料准等熵加载强度等动力学特性实验技术，为开展更多材料的动力学特性研究奠定了实验和理论基础。