Study on the Test Conditions of Micro-hardness

抄録

Several experiments of micro-hardness have been performed on Al and Mg single crystal in order to clarify the effect of test conditions. The micro-hardness increased rapidly at first with the increasing of test load in the small load range, then decreased gradually and became finally independent of the test load. Such phenomena were observed in the test conditions. Firstly, it was supposed that the phenomenon of increasing micro-hardness in the small load range was caused by the external vibrations which originated from the experimental station. Secondly, it was verified that the load-dependency of micro-hardness which showed that the micro-hardness decreased with the increasing of test load was due to the heterogeneous deformation of indentation and the dissimilar indentation with respect to the indentation. So, for the micro-hardness testing it is recommended that the loading rate be kept at about 10μ/sec and the loading time of indenter kept below 10 sec.