| This paper was perfomed to invetigate the effect of extrusion on the mechanical properties of K₂O·6TiO₂/Al composites in order to optimize hot extrusion condition. K₂O·6TiO₂whisker was mixed with Al powder. The mixture was degassed for 1 hour at 450℃ and then pressed under the pressure of 100 ㎫ in vacuum at 600℃. These composites obtained range from 10 to 30 v/o whisker. Hot pressed composites were hot extruded at 500 and 550℃, respectively. Extrusion ratio was 10:1, 15:1, 25:1. After hot extrusion, microstructures observation showed that whisker clustrs strainghtened narrowly parallel to extrusion direction. It was observed that relative density of composites increased as extrusion ratio increase, showing 99.6 % at 10 v/o whisker. The tensile strength at both room temperature and elevated temperature temded to increace WHS extrusion ratio. In extrusion ratio of 10:1, however, tensile strength of the composites with 30 v/o whisker was observed to be lowered compare with that of as-hot pressed composites. As thermal exposure time increased, tensile strength of the composite with 20v/o whisker decreased. This may be attributable to the matrix weakness and reduction of whisker strength due to exit of K ion at elevated temperature. |
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