| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
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| Symposium
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Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
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| Presentation Title |
E-2: Grains Ain't Misbehaving or Going Wild? A Spontaneous Activation of Grain Boundaries Initiating Abnormal Grain Growth! |
| Author(s) |
Klaus-Dieter Liss, Pingguang Xu, Ayumi Shiro, Shuoyuan Zhang, Eitaro Yukutake, Takahisa Shobu, Koichi Akita |
| On-Site Speaker (Planned) |
Klaus-Dieter Liss |
| Abstract Scope |
Unconventional white-beam Laue synchrotron X-ray diffraction was used on fine- and ultra-fine-grained, rolled magnesium alloys during in-situ heating experiments. At high temperatures, reflections of single grains are superimposed on the halo stemming from matrix grains. Some unique grain reflections spontaneously move, indicating grain rotations in response to torque expedited at grain boundaries. When a grain boundary spontaneously activates, the grain can begin to reorient, allowing diffusive mass transport and activating the boundaries of its other neighbors. Now the given grain can freely rotate towards coalescence; however, the multitude of grain boundaries compete in torque orientation and magnitude, resulting in zigzag rotations. After coalescence, the boundaries of the larger grain are still active and continue this scenario of growth, while the majority of the matrix grains remain inactive. The first-time experimental observation of such erratic grain behavior supplies the missing puzzle stone leading to anomalous grain growth, long postulated in literature. |