| 摘要 |
PURPOSE:To enhance the strength of a composite material only by applying cold and hot treatments by alternately subjecting the composite material wherein a fiber is compounded with a polymer material to cooling and heating treatment cooling the composite material at specific temp. and subsequently heating the same. CONSTITUTION:A composite material wherein a fiber is compounded with a polymer material is cooled to 0 deg.C or less and subsequently heated to 100 deg.C or higher. These cooling and heating treatments are alternately applied. For example, the composite material is prepared by mixing a carbon or glass fiber with a polymer material such as an epoxy resin. This composite material is cooled at 0 C or lower, for example, -55 deg.C for 30min and subsequently heated at 100 deg.C or higher, for example, 125 deg.C for 30min and this cooling and heating cycle is repeated a proper number of times. The composite material to which a thermal shock of cooling and heating is applied is markedly enhanced in fatique strength as compared with a composite material to which no thermal shock is applied. |
