DEVELOPMENT STUDY OF HIGH-TEMPERATURE STRUCTURAL MATERIALS OF LAVES PHASE REFRACTORY ALLOYS WITH HIGH RESISTANCE TO CORROSION AND ENVIRONMENT

采用金相、x射线衍射和带能量色散x射线分析的透射电镜研究了1350℃时三元Nb-Cr-Ti合金体系的相图。并通过压缩试验对其高温变形性能进行了研究。在5at之间的成分。%Nb和15at。合金中含有%Nb， 66.7at, %Cr-(33.3-x)at。% Ti-x。在1350℃时，具有六方结构的Laves相与具有fcc结构的C15相处于平衡状态。Laves相与Cr-bcc固溶体直接平衡，不形成任何金属间相。由Laves相和Cr-bcc固溶体组成的共晶路径位于75at之间。%Cr和80at。在三元Nb-Cr-Ti合金体系中添加%Cr。从压缩试验结果来看，由初生Cr-bcc固溶体和Laves相组成的合金的高温变形性能优于由初生Laves相和Cr-bcc固溶体组成的合金。

The phase diagram of ternary Nb-Cr-Ti alloy systema at 1350℃ are investigated by mettallography, X-ray diffraction and transmission electron microscopy equipped with energy-dispersive X-ray analysis. And also, high temperature deformability is investigated by compression test. In the composition between 5at.%Nb and 15at.%Nb in the alloy with 66.7at.%Cr-(33.3-x)at.%Ti-x at.%Nb, C36 Laves phase with dihexagonal structure is in equilibrium to C15 phase with fcc structure at a temperature of 1350℃. And Laves phase are equilibrated directly with Cr-bcc solid solution without forming any intermetallic phases. The eutectic path consisting of Laves phase and Cr-bcc solid solution lies in a composition between 75at.%Cr and 80at.%Cr in the ternary Nb-Cr-Ti alloy system. Form the experimental result of compression test, the high-temperature deformability of the alloy consisting of primary Cr-bcc solid solution and Laves phase is better than that of the alloy consisting of primary Laves phase and Cr-bcc solid solution.