In Situ Micro-Hardness Tests on Brittle Intermetallics for Determining Their Slip Systems

Compression testing has been used to investigate the mechanical properties of brittle intermetallic compounds rather than tensile testing due to their brittleness, but some of the more brittle materials exhibit collapse or crushing during compression testing. This phenomenon can be attributed to defects such as voids or cracks introduced into the specimen during preparation. Micropillar compression testing has been used to reduce specimen volume. Plastic deformation without collapse or crushing was observed using this method. Based on these results, it is believed that plastic deformation occurs when the specimen is small enough to reduce the probability of the presence of internal defects. However, this method is not easy to apply.<br/>Hardness measurements are effective in introducing plastic deformation in small regions. The authors attempted to apply the micro-indentation test to the study of brittle intermetallic compounds such as the Ce₂YNi₉-hR36 compound, and analyzed the slip traces introduced during indentation in comparison with EBSD analysis results. This method allowed us to confirm the slip plane of brittle compounds. The results of crack initiation and propagation observation using a newly developed “in-situ” indenter apparatus are also presented.<br/>This study was financially supported by Iketani Science and Technology Foundation (Grant Numbers 0351211-A and 0363010-C), and JSPS KAKENHI for Scientific Research on Innovative Areas “MFS Materials Science (Grant Number JP18H05482). Parts of this work were also conducted at the Laboratory of Nano-Micro Materials Analysis, Hokkaido University, supported by “Nanotechnology Platform Program” and “Advanced Research Infrastructure for Materials and Nanotechnology in Japan (ARIM)” of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.