초록 ▼

Ⅳ. 연구개발결과
○ 고에너지 X-선 실시간 회절시험(CMWP법, 3D-XRD법)을 위한 합금별 미세조직 조절 (A1, Z1, X02, W05, ZA11, ZW10, ZX10, SEN 합금)
- 실시간 회절시험법에 적합한 평균 결정립도 조절: CMWP ∼15㎛, 3D-XRD 60㎛ 이상
○ 합금 조성별 집합조직 발달 및 전위구동 경향
- Al함유 합금: pyramidal< c+a >전위의 높은 구동, 기저면이 주변형축으로 기울어진 형태의 집합조직
- RE(또는 Ca)함유 합금: Al함유 합금과

Ⅳ. 연구개발결과
○ 고에너지 X-선 실시간 회절시험(CMWP법, 3D-XRD법)을 위한 합금별 미세조직 조절 (A1, Z1, X02, W05, ZA11, ZW10, ZX10, SEN 합금)
- 실시간 회절시험법에 적합한 평균 결정립도 조절: CMWP ∼15㎛, 3D-XRD 60㎛ 이상
○ 합금 조성별 집합조직 발달 및 전위구동 경향
- Al함유 합금: pyramidal< c+a >전위의 높은 구동, 기저면이 주변형축으로 기울어진 형태의 집합조직
- RE(또는 Ca)함유 합금: Al함유 합금과 비교해 상대적으로 높은 non-basal< a > 전위의 구동, 주변형축에 수직된 방향으로 기저면이 기울어지는 집합조직
- Zn-RE(또는 Zn-Ca)함유 합금: non-basal< a > 전위의 높은 구동, 주변형축에 수직된 방향으로 기저면이 기울어진 집합조직
○ 전자현미경 및 전산모사를 이용한 변형기구 해석
- EBSD IGMA 분석: A1 합금은 높은 < c+a > 전위밀도를 보이며, ZW10 합금은 높은 prismatic< a > 전위밀도를 보임.
- VPSC 전산모사 결과 ZW10 합금은 prismatic< a >에 대한 낮은 CRSS 값을 나타냄.

(출처 : 요약문 4p)

Abstract ▼

In order to develop high-performance magnesium alloys, it is essential to optimize alloy composition and microstructure which are based on quantitative analysis of the influence of alloying elements on dislocation slip and grain orientation change accompanied by thermomechanical treatments. The pres

In order to develop high-performance magnesium alloys, it is essential to optimize alloy composition and microstructure which are based on quantitative analysis of the influence of alloying elements on dislocation slip and grain orientation change accompanied by thermomechanical treatments. The present study aims to improve performance of the commercial magnesium alloys and develop new high-performance alloys via in-situ diffraction analysis performed on various alloys using hard X-rays at synchrotron, and data analysis technology. In-situ diffraction study guides to understand the deformation mechanism and microstructure evolution during thermomechanical treatments. The in-situ diffraction experiments were carried out during the deformation of magnesium alloy samples at the high energy material science beamline HEMS P07B at the DESY synchrotron facility in Hamburg, Germany.
For the comparative study of density evolution of dislocations with different Burgers vectors according to alloying elements, which is a main goal of the present project, three groups of alloys were prepared: A1, Z1, X02, ZA11, ZX10 alloys without rare earth elements, and W05, ZW10 alloys containing rare earth elements and SEN-based alloys containing both rare earth elements and Ca. Through the CMWP and 3D-XRD method, the overall dislocation density evolution and grain-level deformation behavior were analyzed according to the strain increase. In all the examined alloys, dislocations with < a > and < c+a > Burgers vectors act as dominant deformation mechanisms, and the marginal change of < c > dislocation density with increasing strain indicates the negligible contribution to deformation. The Al-containing alloys A1 and ZA11 show a marked increase in the < a > and the < c+a > dislocations densities at the same time, while the ZW10 and SEN alloys, which simultaneously contain Zn and Y (or Ca), show the increase in < a > dislocations. Binary alloys containing Y or Ca show a weak increase in < a > dislocations and a relatively large increase in < c+a > dislocations compared to the alloys containing Zn and Y. Through the in-situ 3D-XRD analysis, it was possible to analyze the deformation behavior of each grain at the beginning stage of plastic deformation, including the elastic region. Even in the part corresponding to the elastic region on the tensile curve, small orientation changes were found in a number of grains as the applied external stress increases. This orientation change in the elastic range of 50 N, or less, is the result of deformation occurring at the grain-level. Even if the external stress is low, enough stress can be applied to cause the grain orientation change. High stress applied in grain-level can be understood as a result from the interaction with neighboring grains in terms of grain size, Schmid factor and the orientation relationship. We plan to determine the CRSS values of different dislocations and alloys from the experimental results, such that the influence of the alloy compositions on the dislocations slip can be quantitatively analyzed. In addition to the in-situ diffraction experiments, EBSD IGMA analysis and crystal plasticity simulation using VPSC model were performed. As a result of EBSD IGMA analysis, it was confirmed that < c+a > dislocations were highly activated in the A1 alloy and the ZW10 alloy showed a higher density of prismatic < a > dislocations, which is consistent with the results of CMWP analysis. Furthermore, the VPSC simulation indicated a lower CRSS value for prismatic< a > dislocation slip in ZW10 alloy, in comparison to that of commercial alloys.

(source : Summary 5p)

목차 Contents

• 표지 ... 1
• 제 출 문 ... 2
• 보고서 초록 ... 3
• 요 약 문 ... 4
• SUMMARY ... 5
• 목차 ... 6
• 제 1 장 연구개발과제의 개요 ... 7
• 1-1 연구개발의 필요성 ... 7
• 1-2 연구개발의 최종목표 ... 7
• 제 2 장 국내외 기술개발 현황 ... 7
• 2-1 국내외 기술 및 연구동향 ... 7
• 2-2 현 기술 상태의 취약성 ... 8
• 제 3 장 연구개발수행 내용 및 결과 + 연구추진 진척도 ... 8
• 3-1 연차별 연구개발 목표 및 내용 ... 8
• 3-1-1 연차별 목표 및 핵심내용 ... 8
• 3-1-2 연차별 세부 연구내용 ... 9
• 3-1-3 연구수행 내용 및 결과 ... 10
• 제 4 장 목표달성도 ... 20
• 4-1 2차년도 목표 달성도 ... 20
• 4-2 기술적 성과목표 (정량적 목표) ... 21
• 제 5 장 연구개발 결과의 활용성 ... 22
• 제 6 장 참고문헌 ... 23
• 끝페이지 ... 26