Zr-Nb合金的相变、弹性模量及强度的高温高压原位超声与同步辐射的协同测量研究

Precise measurements on the elastic moduli and strength of optically opaque metals/alloys at extreme high P-T conditions are long-standing problems in the field of high-pressure physics. On the basis of the recent studies on the Nb end member of Zr-Nb system and Nb-based alloys, here, we will perform integrated experiments on the structural stability/phase transitions, elastic moduli and strength of ZrxNb1-x (x=0,0.1,0.2,0.3,0.5,0.8,0.9,1.0) alloys at extreme high-pressure and/or high-temperature using the state-of-the-art techniques of ultrasonic measurements in conjunction with synchrotron x-ray diffraction as well as x-radiographic imaging, complemented with first-principles density-functional theory calculations. In addition to providing important new thermoelasticity data and strength of Zr-Nb alloys, this project also helps for good understanding of the effects of pressure (P), temperature (T) and composition (X) on the stability and elastic/mechanical properties, the mechanism of pressure- and/or temperature-induced phase transitions, as well as the origin of the P-T induced novel physical properties/phenomena of Zr-Nb alloys. These findings/results may provide a strong guidance for the design and preparation of multi-functional Zr-Nb alloys for their technological and engineering applications in extreme environments.

对不透明金属材料或合金在高温高压极端条件下的弹性模量与强度等物理量的精确测量是高压物理领域内长期存在的一个难题。本项目拟应用基于大腔体压机的高压原位超声测量与同步辐射X射线衍射及光谱相结合的协同测量技术，在过渡金属Nb及其合金材料前期高压物性研究的基础上，来系统研究ZrxNb1-x(x=0,0.1,0.2,0.3,0.5,0.8,0.9,1.0)合金在高温高压极端条件下的相变/稳定性，弹性模量及强度等弹性/力学性能；弄清压力(P)、温度(T)及组分(X)对Zr-Nb合金稳定性及弹性/力学性能的影响规律；探索压力、温度及组分对其物理力学性能等调控的可能性。通过本项目所获得的新实验数据，并结合理论计算模拟，加深对Zr-Nb合金在高温高压下的相变机理、优异弹性/力学性能来源及其物理本质的认识，为设计和制备多功能Zr-Nb合金材料在极端条件下的应用，提供重要的实验依据与理论支撑。

目前，过渡金属合金在高压下的弹性模量与强度的精确测量是高压物理与力学领域内长期存在的一个难题，也是其在高压极端条件下应用的重要参数。本项目利用基于大腔体压机的高温高压材料制备技术，并结合高温熔炼实验工艺，通过对压力-温度-组份-保温时间等热力学及动力学参数的调控，实现了对高致密、不同化学组分高温合金ZrxNb1-x (x = 0, 0.1, 0.2, 0.3, 0.5, 0.8, 0.9, 1) 块体聚晶材料的可控制备与性能调控。利用同步辐射X射线衍射/成像及高压原位超声干涉测量实验技术，结合我们新发展的材料强度测量的新方法，研究了Zr-Nb合金材料在高压高温极端条件下的结构稳定性/相变、声速、状态方程、弹性模量及强度等物理力学性能；已完成本项目对Zr-Nb合金材料在高压(高温)极端条件下的同步辐射X射线衍射/成像与原位超声干涉测量研究的相关工作，并获得了压力(P)、温度(T)及组分(X)对Zr-Nb合金体系材料的相变、结构稳定性、弹性模量、强度等物理力学性能的影响规律，并结合理论计算分析，对其相变机理、优异弹性/力学性能来源及其物理本质的有了较深入的认识。此新的实验结果及我们观测到的新实验现象对设计和制备多功能Zr-Nb合金材料，及其在高温高压极端条件下制造业、航空航天或生物材料等领域的应用具有重要意义。