| The effect of Si content on microstructures and mechanical properties in Cu-7ωt% Al alloy has been investigated experimentally for the purpose of establishing industrial application of Cu-Al-Si alloy casting (high silicon aluminum bronze) which is employable under the severely corrosive condition. The results obtained from this study are summerized as follows. 1. As-cast microstructures of Cu- 7ωt% Al alloy are refined markedly with the addition of Si more than 1.5%. 2. Tensile strength and hardness of Cu-7ωt% Al alloy are increased from 35㎏/㎟ to 56㎏/㎟ , from HR_B 20 to HR_B 80, respectively, but elongation is decreased from 70% to 20% with the addition of 2% Si. 3. Tensile strength and hardness of α-aluminum bronze casting which has silicon content of 2% are increased linearly with increasing Al content, but elongation is decreased. 4. Tensile strength and hardness of Cu-Al-Si alloy casting are increased, but elongation is decreased with increasing cooling rate which refine the microstructures of these alloys and suppress the precipitation of γ² phase. 5. Shrinkage of Cu-7ωt% Al alloy is decreased markedely with the addition of (1.5∼2.0%) Si. |
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