Evolution of anisotropic crack patterns in shrinking material layers
Evolution of anisotropic crack patterns in shrinking material layers
复制标题
收缩材料层中各向异性裂纹模式的演变
DOI：
10.1039/d1sm01193f
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发表时间：
2021
期刊：
影响因子：
3.4
通讯作者：
So Kitsunezaki and Ferenc Kun
中科院分区：
文献类型：
--
作者：
Roland Szatmari;Zoltn Halasz;Akio Nakahara;So Kitsunezaki and Ferenc Kun
在基板上的浆料干燥层中出现的各向异性裂纹图案可用于在微电子制造中具有潜在应用的受控裂纹。我们调查这种可能性的裂纹图案的框架中的离散元模型的各向异性裂纹图案的时间和空间演变的薄材料层逐渐收缩。在该模型中，一个均匀的材料被认为是一个固有的结构性障碍，各向异性被捕获的局部内聚强度的方向依赖性。我们表明，存在一个阈值各向异性，低于该阈值裂纹的萌生和扩展是由无序的微观结构，引起细胞裂纹图案。当各向异性的强度足够高时，发现裂纹通过三个不同的阶段发展：对齐的裂纹，切片的样品，在垂直方向上的二次裂纹，最后形成连接的裂纹网络后的二元碎片。各向异性的裂纹图案的结果在碎片的形状各向异性，逐渐得到减少作为二进制碎裂的进行。碎片质量的统计表现出高度的鲁棒性所描述的对数正态函数形式在所有各向异性。
Anisotropic crack patterns emerging in desiccating layers of pastes on a substrate can be exploited for controlled cracking with potential applications in microelectronic manufacturing. We investigate such possibilities of crack patterning in the framework of a discrete element model focusing on the temporal and spatial evolution of anisotropic crack patterns as a thin material layer gradually shrinks. In the model a homogeneous material is considered with an inherent structural disorder where anisotropy is captured by the directional dependence of the local cohesive strength. We demonstrate that there exists a threshold anisotropy below which crack initiation and propagation is determined by the disordered micro-structure, giving rise to cellular crack patterns. When the strength of anisotropy is sufficiently high, cracking is found to evolve through three distinct phases of aligned cracking which slices the sample, secondary cracking in the perpendicular direction, and finally binary fragmentation following the formation of a connected crack network. The anisotropic crack pattern results in fragments with a shape anisotropy which gradually gets reduced as binary fragmentation proceeds. The statistics of fragment masses exhibits a high degree of robustness described by a log-normal functional form at all anisotropies.