低压脉冲磁场对A357合金组织及阻尼性能的影响

Effect of Low Voltage Pulsed Magnetic Field on Microstructure and Damping Capacity of A357 Alloy

研究了低压脉冲磁场对A357合金凝固组织及阻尼性能的影响。结果表明,低压脉冲磁场对A357合金凝固组织中初生α-Al相和共晶Si相具有显著的细化和变质作用。施加磁场处理后,T6态A357合金的阻尼性能显著提高。当在室温、频率为1 Hz和应变振幅为0.01%的条件下,经磁场处理的T6态A357合金的阻尼值达到了0.014 2,较未施加磁场处理的A357合金提高了170%。随着频率的增加,经磁场处理的T6态A357合金的阻尼值逐渐降低。

Effects of low voltage pulsed magnetic field （LVPMF） on the solidified microstructure and damping capacity of A357 alloy were investigated. Experimental results show that primary a-Al phase and eutectic Si phase in A357 alloy treated by LVPMF are refined significantly. A357 alloy treated by LVPMF exhibits much higher damping Capacity than that untreated by LVPMF. Moreover, damping capacity is increased with increasing in temperature, whereas decreased with increasing in frequency. At room temperature, strain amplitude of 0.01% and frequency of 1 Hz, the damping capacity value rea- ches 0. 0142 for A357 alloy with LVPMF treatment. Compared with the A357 alloy without LVPMF treatment, the damping capacity value is increased by approximately 170%. With increasing in frequen- cy, damping capacity of T6-treated A357 alloy after LVPMF treatment is decreased gradually.