Keisuke Matsuura

The effect of second phase on the creep deformation of 6061Al matrix composites.

Abstract Creep behaviour of two types of 6061Al matrix composites, which were reinforced with 10 and 20 vol.% of alumina particles or 11 and 18 vol.% of alumina short fibers, have been investigated at temperatures ranging from 573 to 773 K. Creep curves, stress dependences of the minimum creep rate and the microstructure after creep deformation were examined. A quantitative analysis of creep curves was also carried out by the θ-projection method. The difference in the volume fraction of the reinforcing second phases does not affect the creep strength in both types of composites. Creep strength of the fiber reinforced composites is higher than that of the particle reinforced ones at 673 and 773 K. Parameters determined by θ-projection method are able to describe the creep curves of the composites quantitatively. It has been shown that the precipitation of the solute atoms influences the creep behaviour at 573 K in both composites. The existence of the soft regions around the second phase is suggested in the particle reinforced composite crept under low stress at 773 K.

Creep curves of an aluminium matrix composite reinforced with continuous alumina fibres

Abstract Creep curves of an aluminium matrix composite reinforced with continuous alumina fibres, which were obtained at various stress levels and temperatures between 573 and 773 K, were analytically examined. Most of the creep curve at low stress and the initial part of the creep curve at high stress could be approximately expressed by logarithmic creep; this type of creep may be associated with the exponential creep law of the aluminium matrix.

A singing voice attenuation system using active noise control: Introduction of a widened pipe structure

We have been investigating on the possibility of controlling singing voice using active noise control technology. We proposed a novel structure which introduces a widened portion in the pipe structure. We compared the efficiency of ANC with conventional conduction path pipes, and found that the new structure enhances the ANC performance depending on the phonetic content.

Towards a singing voice attenuation system using active noise control

We have been investigating on the possibility of controlling singing voice using active noise control technology. We proposed a novel structure for conduction pipes with absorption material lining into which the singer can sing into. We compared the efficiency of ANC with conventional conduction path pipes, and found that the new structure enhances the ANC performance depending on the phonetic content.