采用可连续变温测量的多功能内耗仪在离散振动频率分别为0.2,0.3,1.0,2.0和3.0 Hz的条件下测定了多晶纯铝在25℃(→)450℃升降温过程中的内耗峰值温度和相对动力学模量,并根据Arrhenius关系式计算了升降温过程中的扩散激活能和内耗行为特征.结果表明:多晶纯铝在受迫振动时,其升温和降温的内耗品质因子倒数曲线上均出现一个内耗峰,随着离散振动频率的增大,内耗峰峰位向高温方向移动,说明该内耗峰具有弛豫性;该内耗峰是晶界内耗峰,其机制为铝原子在铝/铝晶界的自扩散,其激活能为(2.24±0.03)×10-19 J,指数前因子τ0为10-14 s.
The internal friction (IF) and relative dynamic modulus in the polycrystalline pure aluminum (Al) were measured using a multifunction internal friction apparatus (MFIFA) at frequencies of 0.2, 0.3, 1.0, 2.0 and 3.0 Hz over the wide temperature range between 25 and 450 ℃ with continuous temperature changing. Base on the Arrhenius formula the diffusion activation energy and internal friction behavior features were caculated during increasing and decreasing temperature course. The results show that in the forced vibration of polycrystalline pure aluminum during heating process and cooling process, a distinct IF peak was found in the IF quality factor reciprocal curves. The peak temperature of the IF peak shifted towards higher temperature with increasing frequency,indicating a thermally activated relaxation process. The IF peak was a grain boundary IF peak, which was associated with the diffusive grain boundary of A1/A1. Its activation energy was calculated to be (2.24±0.03) × 10-19 J and the pre-exponential factor τ0 was 10-14 s in IF measurements.
参考文献
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