Kazuhiro Kitamura

Mechanical Properties of Cast Shape Memory Alloy for Brain Spatula

In order to develop a brain spatula or a brain retractor made of a shape memory alloy (SMA), the bending characteristics of the brain spatula of TiNi SMA made by the precision casting were discussed based on the tensile deformation properties of the existing copper and the TiNi rolled-SMA. The fatigue properties of both materials were also investigated by the plane-bending fatigue test. The results obtained can be summarized as follows. (1) The modulus of elasticity and the yield stress for the cast and rolled SMAs are lower than those for the copper. Therefore, the conventional rolled-SMA spatula and the new cast-SMA spatula can be bent easily compared to the existing copper-brain spatula. (2) With respect to the alternating- and pulsating-plane bending fatigue, the fatigue life of both the copper and the SMAs in the region of low-cycle fatigue is expressed by a power function of the maximum bending strain. The fatigue life of the conventional rolled SMA and the new cast SMA is longer than that of the existing copper. The fatigue life of the new cast and rolled SMAs in the pulsating-plane bending is longer than that in the alternating-plane bending. (3) The fatigue life of the rolled-SMA and the cast SMA for alternating- and pulsating-plane bendings can be expressed by the unified relationship with a power function of the dissipated work.

Development of Efficient Metal Catalyst Support

A new wire mesh metallic catalyst support has been studied by using a stainless heat resistant steel of including aluminum. This catalyst support was improved for the metal honeycomb catalyst support that had been put to practical use. The wire mesh catalyst support was made in the following procedures. First, it was made from flat plate made by the stainless steel from the machining. Second, the low oxygen atmosphere in the heat treatment furnace did the aluminum extraction processing. Third, the aluminum oxide layer was made on the surface of catalyst support by furnace in air. Metal honeycomb catalyst has been made for several years by this method. The aim of this study was to evaluate the aluminum oxide layer on the surface of wire mesh catalyst support. The aluminum oxide surface was measured using scanning electron microscopy (SEM) and X-ray reflection diffraction (XRD). This catalyst support has the performance similar to the conventional metal honeycomb catalyst support.

Development of the Technology Teaching Materials Using Ti-Ni Shape Memory Alloy

This paper shows the development of the technology teaching materials using Ti-Ni shape memory alloy. The teaching material was made by shape memory alloy spring, plastic bottle, nut, magnet, battery box, wood plate, Styrofoam block, current cord, battery snap and drawing paper. The shape memory alloy was memorized in the shape of a spring using steel bolt. The spring was self-heated by the battery current and it returned to the original shape. The weight made with a nut was attached to the spring. First, the spring was lengthened from the weight and touched the lower electrode. Second, the spring was flipped up and disconnected the electrode. Third, the weight went up and down continuously. Students were made in the production of the teaching materials and they learnt that the shape memory alloy was able to convert the energy of electricity into the mechanical energy.

Ti-50.2Ni-5Zr Shape Memory Alloy Square Rots Production by the Casting Technique

The purpose of this study is to make the Ti-Ni-Zr specimen using casting method from P/M ingot and evaluates the shape memory behavior. All samples were square rod shape made by centrifugal casting. The size of all samples was 1 mm wide, 1.3 mm height and 37.5 mm length. The transformation behavior during cooling and heating was investigated using a differential scanning calorimeter (DSC). The phase constituent was determined by XRD analysis from 20 °C to 150 °C. Mechanical properties of the shape memory effects were measured using a tensile machine at 25 °C. The samples were annealed at 400 °C, 500 °C and 600 °C for 3.6 ks followed by water quenching. After annealing, specimens were cold rolled at 0 % (no rolling) and 10 %. The Ti-Ni-Zr square rod specimens are fabricated by centrifugal casting using P/M ingot. All samples had shape memory behavior. From DSC measurement, the highest reverse martensitic transformation temperature is 120 °C. From tensile test, the Luders like deformation stress were not constant and dependence of heat treatment conditions was not clarified. However, 10% cold rolling specimen, shape memory characteristics were stabilized.

Effect of Heat Treatment Temperature on the Mechanical Property in Cast TiNi Shape Memory Alloy

The heat treatment effect of a cast shape memory alloy (SMA) from self-propagating high temperature synthesis (SHS) ingot was investigated. The composition of SHS ingot was Ti-50.8at%Ni. DSC and Tensile test specimens were cast by lost-wax process from SHS ingot. The heat treatment conditions were 400°C-60min., 500°C-60min. and 600°C-60min. for DSC and 400°C-60min. and 500°C-60min. for tensile test. Transformation temperatures were measured by differential scanning calorimetry (DSC). Mechanical properties were measured by a tensile test at several temperatures. The effects of heat treatment temperatures were same as a general TiNi wire material.