Abstract

The dynamics of deformation bands in Al–Mg alloy has been investigated synchronously in situ by two methods: acoustic emission (AE) and high-speed (20 000 fps) video recording of a sample surface deformed at a specified stress rate \({{\dot {\sigma }}_{0}}\). It is established that a band nucleates at a random site on the lateral surface of planar sample and grows in the form of a needle-shaped embryo band at an angle of about 60° with respect to the extension axis, with a tip velocity of up to ~10 m/s. The embryo-band nucleation, growth, and outcrop onto the opposite lateral surface is accompanied by generation of a broadband AE signal in the frequency range of ~10²–10⁶ Hz. The low-frequency component of the AE signal in the range of ~0.1–1 kHz is related to the macroscopic band behavior, and the high-frequency component in the range of ~0.1–1 MHz contains data on the mesoscopic events, related to jumps in the velocity of embryo-band tip and its outcrop onto the external sample surface. The mechanisms of AE signal generation have been discussed.

中文翻译：

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Al-Mg合金中变形带形成与声响应的相关性的高速原位研究

摘要

已通过两种方法在原位同步研究了Al-Mg合金中变形带的动力学：声发射（AE）和高速（20 fps）视频记录在指定应力率下变形的样品表面\（{ \ dot {\ sigma}} _ {0}} \）。已经确定，条带在平面样品侧面的随机位置成核，并以针状胚胎带的形式相对于延伸轴以约60°的角度生长，尖端速度为至〜10 m / s。胚胎带的成核，生长和在相对侧面上的露头伴随着〜10 ² –10 ⁶频率范围内宽带AE信号的产生赫兹。AE信号在〜0.1–1 kHz范围内的低频分量与宏观频带行为有关，而〜0.1–1 MHz范围内的高频分量包含有关介观事件的数据，与胚带尖端和其露头的速度跳跃到外部样品表面。已经讨论了AE信号产生的机制。