Hisaki Okamoto

Crossings of thin-plate martensites in an Fe-Ni-C alloy

Abstract Crossings of the thin-plate martensites in an Fe-31wt.%Ni-0.28wt.%C alloy were observed by means of transmission electron microscopy. An analysis was made in terms of the magnitudes of the resolved shear strains of the 23 crossing plates on the possible {112} 〈 111 〉 deformation twinning systems in a crossed plate and the shape strain directions of the crossing plates. The obtained results results are as follows. 1. (1) The 24 variants of martensites with {3,10,15} type habit planes can be grouped into the six {110} plate groups of the austenite by their shape strain directions. When the crossed plate with (3, 15, 10) habit plane is intersected with one of the other 23 crossing plates, the deformation modes at the crossed region of the crossed plate can be classified by each plate group. 2. (2) The crossing mechanism of two plates can be considered as follows: when a crossing plate grows into a pre-existing plate, the crossed region of the latter is deformed by the shape strain of the former. If this deformation produces a certain amount of stress on the other side of the crossed plate, the same variant as the crossing plate is nucleated and grows.

Effects of Microscopic Spherical Particles Mixed in Lubricating Oil on Frictional Characteristics of Linear Slide Guide

In order to develop a superior linear slide guide having friction coefficient independent of sliding velocity, the authors have proposed a method to supply microscopic spherical particles to hardened sliding surfaces finely finished by lapping. The frictional characteristics of a slide guide to which the method was applied were investigated using a model of machine tool’s slide guide. Experiments were carried out at the sliding velocity ranging from 1 to 6000 mm/min. Adding spherical particles with a 5 μm diameter to a vegetable lubricating oil having a viscosity of 215 mm2 /s leaded to a constant friction coefficient excluding ultra-low sliding velocity range.Copyright