Chen Ying, Schuh Christopher A
Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2007 Jan 19;98(3):035701. doi: 10.1103/PhysRevLett.98.035701. Epub 2007 Jan 17.
We study the percolation aspects of diffusional "Coble" creep on heterogeneous grain boundary networks, assuming free grain boundary sliding. A novel percolation threshold is obtained for the honeycomb lattice when two representative types of grain boundaries are randomly distributed, p(cc)=0.5416+/-0.0036. The creep viscosity diverges near the percolation threshold with power-law exponents t=1.69+/-0.09 and s=1.88+/-0.12, different from the standard conduction and rigidity percolation exponents. The moments of both the force and flux distributions all conform to finite-size scaling at p(cc), but with new exponents. These new scaling behaviors seen in the creeping system are proposed to arise from the unique coupling of both force and flux balances in the network.
我们研究了在假设自由晶界滑动的情况下，扩散性“柯布尔”蠕变在非均匀晶界网络上的渗流特性。当两种具有代表性的晶界类型随机分布时，得到了蜂窝晶格的一个新的渗流阈值，(p(cc)=0.5416±0.0036)。在渗流阈值附近，蠕变粘度以幂律指数(t = 1.69±0.09)和(s = 1.88±0.12)发散，这与标准的传导和刚性渗流指数不同。力和通量分布的矩在(p(cc))处均符合有限尺寸标度，但具有新的指数。在蠕变系统中观察到的这些新的标度行为被认为源自网络中力和通量平衡的独特耦合。
