Heterogeneity of dislocation substructure in polycrystalline metals and its influence on mechanical properties

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H06933
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Kyushu University
• Principal Investigator: Yamasaki Shigeto 九州大学, 総合理工学研究院, 助教 (00804741)
• Research Collaborator: Mitsuhara Masatoshi ; Nakashima Hideharu
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 転位 / 電子顕微鏡 / 金属材料 / 塑性変形

Outline of Final Research Achievements

Dislocation substructure development in pure nickel deformed by SEM in-situ tensile test was observed by SEM electron channeling contrast method. In pure nickel, an increase in slip lines and dislocation pileup near grain boundaries were observed. In the case of hexagonal titanium alloys, dislocations mainly active in prism slip and basal slip were observed in the grains. On the other hand, in the vicinity of grain boundaries, dislocation lines considered to be active on the pyramidal surface were frequently observed. It is understood that this is because, in the hexagonal titanium alloy having low crystal symmetry, the activity of pyramidal slip is activated in the vicinity of the grain boundary in order to maintain the continuity of displacement with adjacent grains.

Free Research Field

金属材料学

Academic Significance and Societal Importance of the Research Achievements

本研究成果より、強化が施された実用合金ではSEM-ECCI法により材料中の転位組織の発達やその不均一性を観察できることが明らかとなった。転位組織の発達挙動を理解することは材料の力学特性を理解する上で非常に重要であり、本手法は実用合金の組織評価に関して極めて有用な方法である。