Intergranular damage and failure mechanisms in high-strain-rate superplastic nanoceramics

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420700
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Inorganic materials/Physical properties
• Research Institution: Kitami Institute of Technology
• Principal Investigator: Hiraga Keijiro 北見工業大学, 工学部, 教授 (80354190)
• Co-Investigator(Kenkyū-buntansha): KIM Byung-Nam 国立研究開発法人・物質・材料研究機構, 主席研究員 (50254149) ; MORITA Koji 国立研究開発法人・物質・材料研究機構, 主幹研究員 (20354186)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 超塑性 / 高ひずみ速度 / 粒界損傷 / 微視き裂 / 引張破断 / 偏析 / 粒子分散 / 複合化

Outline of Final Research Achievements

The relationship was investigated between intergranular cavitation damage and tensile failure in tetragonal-zirconia-based materials: doped and undoped high-purity materials and composite materials dispersed with second and/or third phases. The results showed that microcracks caused from extensive cavity coalescence led to superplastic tensile failure, independently of the compositional and microstructural varieties in the present materials. The results also showed that the effects of the doping and dispersed phases depended strongly on the strain rate. The doping or the second- and/or third-phase-dispersion that enhanced ordinary superplasticity at strain rates at around 1E-4～1E-3 /s was rather found to lower the tensile elongation at strain rates higher than 1E-2 /s. The present study indicated that such strain-rate dependence may arise from the strong strain-rate dependence of cavity formation in the doped or the composite materials.

Free Research Field

材料工学