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Although titanium is a very useful material and becoming more in demand, we are faced with difficulties in machining the material. By applying ultrasonic vibration to the tool tip, interrupted cutting can be applied. Using ultrasonic vibration-assisted cutting of titanium alloy, we succeeded in reducing the cutting force. This technology enables us to improve tool wear and surface roughness of the workpiece. In regards to cutting fluid supply methods, it was found that semi-dry cutting was the most suitable for ultrasonic vibration-assisted cutting of titanium alloy.

Abstract. It is well known that the Fe based alloys can exhibit shape memory effect due to the y to E martensitic transformation. The effect may not be as striking as observed in the NiTi alloy but it might become attractive fkom the practical point of view. In this work, two compositions of Fe-Cr-Ni-Mn-Si(-Co) stainless steel based shape memory alloy, prepared by the VIM technique, will be presented. The results are good with shape recovery of 95% for a pre-strain of 4% after some training cycles. In terms of workability the alloys produced are worse than the usual AISI304. However, adjusting the thermo-mechanical processing, it is perfectly possible to produce wire as thin as 1,20mm in dia. or down.

Internal friction measurements as a function of temperature and strain amplitude have been performed on polycrystalline CuZnAl and Ti Ni alloys. These measurements show a typical "critical" behaviour round the temperature of the martensitic transformation : discontinuities in the internal friction curves, important decrease of some elastic constants and a thermal hysteresis between heating and cooling. In order to explain these results, theoretical calculations based on a Landau theory of first order phase transition have been performed. An important strain amplitude dependence is taken into account. It is assumed that the order parameter has the same dynamical behaviour as the one of the dislocations when they break away from pinning points. The thermal hysteresis is then explained without references to the influence of internal stresses.

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