| Two types of lead-composite reinforced with steel fiber were prepared by a casting method; one was fabricated with solder-coated steel fiber, and the other the solder-ancoated steel fiber. The mechanical properties, plastic behaviors, and fracture modes of these composites have been studied, and the mechanical properties of the steel fiber have also been investigated on the variation of annealing temperature. The ultimate tensile strength of the composite with solder-coated steel fiber is in good agreement with the theoretical value shown by rule of mixture. However, the value of tensile strength of the composite with solder-uncoated steel fiber shows a slight deviation from the value of the rule of mixture. The stress-strain curves of all the composites can be divided into two regions, corresponding to crack initiation and crack propagation. The stress-strain curve of the composite with solder-coated steel fiber shows a continuity in the former region, however that of the composite with solder-ancoated steel fiber shows a discontinuity in the same region. In the case of composite having solder-coated steel fiber the fracture of steel fiber occurs necessarily at the fracture surface of composite, while in the case of the latter composite with solder-uncoated steel fiber the fiber fractures randomly in the composite. The variation in ultimate tensile strength of the steel fiber with annealing temperature consists of three stages; first stage ranged from 25°to 300℃ shows a nearly constant strength, second stage from 300° to 600℃ has a strength decreased rapidly with the increase in temperature, and third stage which is above 600℃ shows a nearly constant value of strength as in the case of the first stage. |
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