Study on the Forming-Ability of Metastable Phases in Vapor Quenched Alloys Using High Temperatrue X-ray Diffraction

在本项目中，我们研究了溅射（高能态气相淬火）非平衡合金的结构和物理性能的温度依赖性，得到了以下结果：1)利用本基金引进的安装在x射线衍射设备上的高温样品台，可以观察到350 ~ 850 ^ C之间的x射线衍射图。2)观察了直流面向靶型溅射制备的Fe-Cu-Ag非晶合金的x射线衍射、磁化、电阻率、差示扫描量热和穆斯堡尔谱。非晶合金在400k以上结晶，并在相同浓度下转变为亚稳fcc相。在670 k以上，它们分离为纯bcc Fe和纯fcc Cu和Ag。3)我们观察了非平衡态Fe- w合金的x射线衍射图、磁化率和电阻率。非平衡富铁bcc相在770 K以上分离成富铁α相和金属间化合物λ相。非晶相表现出较高的热稳定性，结晶温度约为1170 K。在1170 k以上，它转变为相和bcc相，但不转变为相，即高温平衡相。4)观察了非平衡态Fe-Pd合金的x射线衍射图、磁化和磁致伸缩。非平衡富铁bcc相在470 K以下保持亚稳相，但在470 ~ 570 K时分离为富铁bcc相和富pd fcc相。在570 K以上，相分离增强，无序fcc相变为L1_0型有序相。这些实验结果表明，退火从非平衡相过渡到平衡相过程中亚稳相的形成突破了基于平衡热力学的经典冶金理论。我们打算做EXAFS和中子衍射的测量。少

In this project, we studied temperature-dependence of the structure and physical properties of nonequilibrium alloys produced by sputtering (vapor quenching process from high energy states) and obtained the following results.1) Using the high temperature sample stage, which was introduced by the present grant and installed on the X-ray diffraction equipment, we could observe X-ray diffraction patterns temperatures between 350 - 850 ^ﾟC.2) We observed X-ray diffraction patterns, magnetization, electrical resistivity, differential scanning calorimetry and Mossbauer spectra for amorphous Fe-Cu-Ag alloys produced by DC facing target type sputtering. The amorphous alloys crystallize above 400 K and transform to a metastable fcc phase with the same concentrations. They separate into pure bcc Fe and the pure fcc Cu and Ag above 670 K.3) We observed X-ray diffraction patterns, magnetization and electrical resistivity for nonequilibrium Fe-W alloys. The nonequilibrium Fe-rich bcc phase separate … More s into a more Fe-rich alpha phase and an intermetallic compound, the lambda phase, above 770 K. The amorphous phase displays high thermal stability and the crystallized temperature is about 1170 K. Above 1170 K. it transforms to the lambda phase and the bcc phase, but dose not transform to the mu phase which is the high temperature equilibrium phase.4) We observed X-ray diffraction patterns, magnetization and magnetostriction of nonequilibrium Fe-Pd alloys. The nonequilibrium Fe-rich bcc phase is maintained as a metastable phase below 470 K, but it separates into a more Fe-rich bcc phase and a Pd-rich fcc phase at 470 - 570 K. Above 570 K, moreover, the phase separation is enhanced and the disordered fcc phase becomes the L1_0 type ordered phase.These experimental results indicate that the metastable phase formation in the transient process from nonequilibrium phases to equilibrium phases by annealing breaks through the classical metallurgy based upon the equilibrium thermodynamics. We intend to do measurements of EXAFS and neutron diffractions. Less