Study about indentation with pyramidal indenter based on ball indenting theory (1st, theoretical equation of ultramicro indentation)

摘要

By the investigation about hardness experiments with conical and pyramidal indenters studied until now, it is known that the indentation processes with a triangular pyramidal indenter having obtuse apex angle are equivalent to that with a hallindenter having non-initial elastic contact between an indenter and a specimen. Next, the ultra-micro indentation experiments [maximum indenters 's load: 98 mN - 9.8 mN] are carried out with Berkovich indenter to the standard hardness block of HMV 100(brass) and HMV 700(steel). It is shown that the exponent of unloading(recovery) curve is equal to that of the hall indenter. And the geometrical relationships between indentation and triangular impression are established. Furthermore, the new concept isintroduced that the indentation processes with a triangular pyramidal indenter correspond to that of the hall indenter using the corresponding hall's indentation processes. As a result, the theoretical equation of ultra-micro indentation is deduced.Finally, the validity of this theoretical equation is discussed.