Ti-Ni-Al 形狀記憶合金의 相變態 및 熱싸이클에 의한 疲勞特性

다국어 초록 (Multilingual Abstract)

The martensitic transformation behavior of TiNi alloys is considerably affected by alloying elements and heat treatment conditions.
In order to investigate the effect of Al addition on the martensitic transformation behavior and fatigue characteristics by thermal cycles in TiNi alloy, electric resistivity measurement, X-ray diffractometer and electron dispersive analysis X-ray have been performed in this study.
Three types of heat treatments were applied to these specimens:
(1) Solution treatment(850℃×1hr/I.W.Q.).
(2) Aging treatment(Sol.-300∼700℃×1hr/I.W.Q.).
(3) Annealing after 30% cold working (Sol.-C.R.-300∼700℃×1hr/I.W.Q.).
The experimental results are as follow:
1. Ms temperature of TiNiAl markedly decrease with the increase of Al concentration and R-phase have been formed along the grain boundary.
2. Ms temperature decreases with the increase of aging temperature before cold working, while it increase markedly with the increase of annealing temperature after cold working.
3. Ms temperature has considerably been decreased with increasing the number of thermal fatigue cycles irrespective of Al contents and heat treatment conditions. However, it was nearly constant after critical number of thermal fatigue cycles.
4. The two-way memory effect becomes more strange in addition of 2.0at.%Al than that of 1.0at.%Al and also appeared considerably with the increase of aging temperature. The two-way memory effect was detected more strongly for the case when 2.0at.%Al is added than that of the 1.0at.%Al. It also becomes more patent with the increase of aging temperature.

목차 (Table of Contents)

• 목차
• I. 서론 = 5
• II. 실험방법 = 8
• 2-1. 시료 제작 = 8
• 2-2. 조직 관찰 = 10
• 2-3. 전기저항 측정 = 10
• 2-4. X-선 회절 시험 = 11
• 2-5. 열피로 시험 = 11
• 2-6. 형상회복률 측정 = 12
• III. 실험 결과 및 고찰 = 14
• 3-1. 광학 현미경 조직 = 14
• 3-2. 변태온도에 미치는 가공열처리의 영향 = 15
• 3-3. X-선 회절 시험 = 17
• 3-4. Al첨가 및 가공열처리에 따른 형상회복률 = 17
• 3-5. 변태온도에 미치는 열피로의 영향 = 18
• 3-6. 형상회복률에 미치는 열피로의 영향 = 20
• 3-7. 투과 전자 현미경 관찰 = 38
• IV. 결론 = 41
• References = 42
• ABSTRACT = 44