Key Laboratory of Automobile Materials, Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun 130022, China.
Phys Chem Chem Phys. 2011 Dec 28;13(48):21328-32. doi: 10.1039/c1cp22748c. Epub 2011 Oct 31.
Young's modulus (Y) of nanostructured materials (NSs) free of porosity is modeled with regard to the coordination number imperfection at grain boundaries. In light of it, Y of NSs is suppressed substantially in the whole solid temperature range, differing from the case of nanocrystals (NCs) where Y is enhanced at lower temperature (T) but weakened at higher T. It is found that, similar to NCs, the thermally-driven decline associated with the melting point depression plays an increasing role in suppressing Y of NSs on raising T. On the other hand, the lattice expansion and the bond weakening lead to a further suppression in Y of NSs independent of T, while the lattice contraction and the reinforced bonding strength result in an enhancement in Y of NCs, which should be responsible for the distinction in Y between NSs and NCs. The established functions were supported by available experimental and computer simulation results.
针对晶界配位数缺陷，建立了无孔隙纳米结构材料（NSs）的杨氏模量（Y）模型。根据这一模型，NSs 的 Y 在整个固态温度范围内都受到了显著抑制，这与纳米晶体（NCs）的情况不同，NCs 的 Y 在较低温度（T）下增强，但在较高温度下减弱。研究发现，与 NCs 相似，与熔点降低相关的热驱动下降在提高 T 时对抑制 NSs 的 Y 起着越来越重要的作用。另一方面，晶格膨胀和键弱化导致 NSs 的 Y 进一步受到抑制，与 T 无关，而晶格收缩和增强的键合强度导致 NCs 的 Y 增强，这应该是 NSs 和 NCs 之间 Y 差异的原因。所建立的函数得到了可用的实验和计算机模拟结果的支持。
