粘弾性圧子力学の構築とミクロ領域におけるレオロジー計測

抄録

The indentation contact hardness has long been utilized in various engineering fields as well as in scientific studies, since the pioneering works conducted by A. Martens (1898), J.A.Brinell (1900), and E. Meyer (1908). The upsurges of electronics, and computer science and engineering in 1980s lead to the development of instrumented micro/nano-indentation test systems that enable to examine the mechanical properties (elastic modulus, yield strength, hardness, etc.) in micro/nano-scales. These conventional test systems, however, can only measure the indentation load P and penetration depth h hysteresis relation (P -h relation) in a precise manner, and then estimate the mechanical properties through the elastic assumptions to approximate the indentation contact area A at the indentation load P. The present indentation contact mechanics, therefore, cannot be applied to very ductile materials, time-dependent-viscoelastic materials, as well as coating/substrate composite materials, for this elastic assumption/approximation is by no means applied to these nonlinear materials. The author invented a novel instrumented indentation test system, the indentation microscope, that is capable of measuring the in-situe contact area A along with P and h, allowing the rheological characterization of monolithic as well as composite materials with any linear/nonlinear deformation and flow. In the present feature article, the author addresses the viscoelastic indentation contact mechanics, including the principle, theoretical considerations, and the applications.