X선 정량분석법에 의한 3원 Ti-Al-Cr계 상태도 검증에 관한 연구

A Study on the Verification of Ternary Ti-Al-Cr System Phase Diagram Using Quantitative Analysis Method

분석전자현미경 X선 정량분석법을 이용하여 1273 K 및 1473 K에 대한 Ti-Al-Cr 3원계 평형상태도를 작성하였다. 각 상의 식별을 위해 미세구조 관찰 및 선택 영역의 전자회절 분석하고, 각 상으로부터 특성 X선을 측정하였다. 1273 K에서는 (α₂+B2+ r. B2+ r + Laves. r + Laves + Ll₂의 3상 영역이 존재하였다. 1473 K에서는 Laves상은 확인되지 않았으며, α₂상이나 B2상은 각각 α상과 β상의 불규칙상태로 존재하였다. 즉, 1473 K에서는 α + β + r 와 β + r + Ll₂의 3상 영역이 관찰되었다. 평형온도가 1473 K에서 1273 K으로 낮아지면, α + β + r (혹은 α₂ + B2 + r) 의 3상 영역이나 β + r(혹은 B2 + r상)의 2상 영역이 Al-poor 측으로 확장한다.

An equilibrium state phase diagram of Ti-Al-Cr ternary system for 1273 K and 1473 K was constructed by X-ray quantitative analysis method in analytical electron microscopy. Microstructural observations and selected area electron diffraction analyses were conducted for phase identification and characteristic X-rays were measured from each phase. The results are as follows. At 1273 K, three-phase regions such α₂+B2+ r, B2+r+Laves and r+Laves+Ll₂ were observed. At 1473 K, no Laves phase was observed, and α₂ phase and B2 phase existed as irregular phase in α phase and β phase, respectively. Thus, at 1473 K, a three-phase region α+β+r phases and β+r+Ll₂ phases were observed. As the equilibrium temperature decreases from 1473 K to 1273 K, the two-phase region of α+β+r(or α₂+B2+ r) and β+r (or B2+r phase) regions were extended to Al-poor concentration as the temperature decreases.