The effects of severe plastic deformation on properties of AA1100 and AA2024 including the ultrasound velocity and the shear strength during multi-axial compression (MAC) are studied. Additionally, optical microscopy, scanning electron microscopy, and X-ray energy-dispersive spectroscopy are utilized. For both AA1100 and AA2024, an opposite trend is reported in the shear strength and the sound velocity versus deformation strain of MAC. At high strain range, AA1100 and AA2024 samples reach a plateau in the strength due to the occurrence of dynamic recovery. On the other hand, the sound velocity is shown to decrease 11% and 15% for AA1100 and AA2024, respectively. Furthermore, the microstructural evaluation reveals that during severe plastic deformation, grain refining for both aluminum alloys occurs. Remarkably, elongated precipitates for severely deformed AA2024 samples are observed. Both an increase in grains boundaries followed by grain refining and elongated precipitates contribute to ultrasonic wave scattering. The presence of such scattering sites is responsible for a noticeable decrease in sound velocity.

中文翻译：

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严重变形铝合金的声速：AA1100 和 AA2024

研究了严重塑性变形对 AA1100 和 AA2024 性能的影响，包括多轴压缩 (MAC) 期间的超声速度和剪切强度。此外，还使用了光学显微镜、扫描电子显微镜和 X 射线能量色散光谱。对于 AA1100 和 AA2024，MAC 的剪切强度和声速与变形应变呈相反的趋势。在高应变范围内，由于发生动态恢复，AA1100 和 AA2024 样品的强度达到平台。另一方面，AA1100 和 AA2024 的声速分别降低了 11% 和 15%。此外，微观结构评估表明，在严重塑性变形期间，两种铝合金都会发生晶粒细化。值得注意的是，观察到严重变形的 AA2024 样品的细长沉淀物。晶粒边界的增加以及晶粒细化和细长的沉淀都有助于超声波散射。这种散射点的存在是声速显着降低的原因。