HOME > 연구물소개 > 나노인덴터응용 Rheo 평가
 
 
 
 
 
 
     
나노인덴터를 이용한 레오로지 소재의 물성평가를 알려드립니다.

 
자동차 및 항공기 산업에서의 고강도-경량 부품의 필요성이 증가하고 있음
Thixo/Rheo forming 과 같은 반용융 성형 공정에 의한 Al-Si 합금 부품의 제작이 활발히 연구 되어 왔음. 최근의 연구는 Rheoforming 에 대한 연구가 주류를 이루고 있음.
 
나노압입실험, 비커스 경도실험, 광학현미경 관찰 및 AFM 관찰
레오 A356-T5 합금의 시효경화특성에 대하여 연구
공정영역에 초점을 두고 연구를 수행. Al-초정영역과 비교
 
 
 
AFM scan showing eutectic silicon particles
AFM scan showing primary Al region
 
Load-depth curves for both eutectic and primary Al regions
 
CSM pre-test results: Indentation arrays (5×5) in the as-rheo-cast A356 alloy
 
 
 
 
1. Grain size 분류
 
 
 
2. Vickers hardness test
 
 
Table 1 Vickers hardness with casting at GS1 (grain size < 70μm)
Position GS1 Mean(kgf/mm2)
Rheo 53.6 59.1 61.9 58.2
Thixo 75.2 77.1 65.7 72.7
 
Table 2 Vickers hardness with casting at GS2 (70μm ≤ grain size <100μm)
Position GS2 Mean(kgf/mm2)
Rheo 51.3 53.6 52.4 52.4
Thixo 72.4 65.7 71.5 69.9
 
Table 3 Vickers hardness with casting at GS3 (100μm < grain size)
Position GS3 Mean(kgf/mm2)
Rheo 46.3 46.8 42.4 45.2
Thixo 54.2 55.3 58.5 56.0
 
 
 
3. Nanoindentation test
 
Table 4 Average-hardness with casting process at GS1 (Calculation range of average =500~1500nm)
Position GS1 Mean (GPa)
Rheo 1.28 1.23 1.18 1.32
Thixo 1.43 1.40 1.31 1.38
 
Table 5 Average-hardness with casting process at GS2
Position GS2 Mean (GPa)
Rheo 1.01 1.14 1.15 1.10
Thixo 1.22 1.21 1.18 1.20
 
Table 6 Average-hardness with casting process at GS3
Position GS3 Mean (GPa)
Rheo 0.83 0.83 0.80 0.82
Thixo 1.16 1.08 1.11 1.12
 
(a) (b) (c)
Fig. 4 Nanoindentation of GS1 in rheo-cast
(a)AFM image (b)load-displacement curve (c)hardness-curve
 
(a) (b) (c)
Fig. 5 Nanoindentation of GS1 in thixo-cast
(a)AFM image (b)load-displacement curve (c)hardness-curve
 
(a) (b) (c)
Fig. 6 Nanoindentation of GS2 in rheo-cast
(a)AFM image (b)load-displacement curve (c)hardness-curve
 
(a) (b) (c)
Fig. 7 Nanoindentation of GS2 in thixo-cast
(a)AFM image (b)load-displacement curve (c)hardness-curve
 
(a) (b) (c)
Fig. 7 Nanoindentation of GS3 in rheo-cast
(a)AFM image (b)load-displacement curve (c)hardness-curve
 
(a) (b) (c)
Fig. 7 Nanoindentation of GS3 in thixo-cast
(a)AFM image (b)load-displacement curve (c)hardness-curve