| Title |
Effect of composition and heat Treating Condition on Damping Capacity of Al - Zn Alloy |
| Authors |
한기우(Ki Woo Han); 최종술(Chong Sool Choi) |
| Abstract |
Variation of damping capacity with cooling rate and aging condition was investigated in Al-40% Zn, Al-60% Zn and Al-78% Zn alloys. Additional investigation for structural changes due to different cooling rate was made in those alloys. The Al-Zn alloys were found to show constant values in damping capacity regardless of maximum surface strain, The damping capacities of the Al-40% Zn and Al-60% Zn alloys were increased with decreasing cooling rate. This may be due to increase in βphase precipitation in accordance with decrease in cooling rate. However, the Al -78% Zn alloy showed high damping capacity with increasing cooling rate. This was because at the rapid cooling rate the two phases(α+β) were decomposed into homogeneous and fine grain structure by spinodal decomposition, while at the slow cooling rate the coarse lamella structure was formed by discontinuous precipitation. The damping capacities of the water-quenched Al-40% Zn, Al-60% Zn and Al-78% Zn alloys were increased with aging time at i50℃ and 250℃. However, the damping capacity of the Al-60% Zn alloy was decreased on further aging above critical times at 150℃ and 250℃, because coarsening in the lamellar structure of the alloy occurred on aging above the critical time at each temperature. |