Titanium 첨가에 의한 NiAI/NiAI 2 상 합금의 미세조직제어 = Transformations;Microstructure Control of NiAl/Ni3AI Two-Phase Alloy by Addition of Titanium

다국어 초록 (Multilingual Abstract)

In the previous study, the β+γ' alloy containing Ti and C showed a more refined mesh microstructure than the lamellar microstructure. This study revealed that the titanium among alloying elements helped to refine the microstructure. The M_s temperature of NiAl lowered rapidly with an increasing titanium content. This effect therefore contributed to the formation of the fine microsturucture. In the case of a low titanium content(below 2.2at.%), the M_s temperature was above ∼255℃, and when the martensite was heated, the exothermic β'→Ni_5Al₃ transformation appeared first. Because the martensite twins could be inherited during the β'→Ni_5Al₃ transformation, the lamellar β+γ' structure similar to martensite plates was finally formed. However, in the case of a high titanium content, the M_s temperature sufficiently lowered, so the endothermic β'→β transformation could occur before the β'→Ni_5Al₃ transformation. The endothermic transformation extinguished the martensite plates, therefore allowing the mesh microstructure to be independently formed from the martensite plates.

목차 (Table of Contents)

• 1. 서론
• 2. 실험 방법
• 3. 실험 결과
• Mesh 형태의 β+γ' 2상 조직의 생성
• DTA에 의한 상변태 과정 분석
• γ'상의 석출 거동
• 4. 고찰
• Ti 함량에 따른 Ms 온도의 변화
• 상변태 과정의 변화에 따른 미세조직 변화
• 5. 결론
• 후기