Study of microscopic mechanism of plastic deformation in inorganic materials with non-periodic structure

准晶和金属玻璃都具有非平移对称结构，它们都可以通过滑移过程进行塑性变形。本研究的目的是通过广泛变形条件下的实验和计算机模拟，阐明这些非平移对称材料的微观滑移变形机制。（1）通过对各种准晶的高温变形实验，阐明了以下事实：（a）任何准晶只有在0.75Tm以上才能发生塑性变形（Tm：熔点），屈服应力随温度升高而迅速降低，（B）准晶通常表现出明显的加工软化，（c）加工软化是由于活化焓降低而发生的。基于对模型准晶位错的计算机模拟，提出了准晶中位错滑移是由相子壁产生的阻力所引起的 ...更多信息 由于准周期Peierls势，其速率由高温下的扭结对形成控制。变形行为很好地解释了模型，其中在无相子准晶上，位错迁移率由在大Peierls势下的扭结对形成所控制，而当相子缺陷密度随塑性变形而增加时，则受小Peierls势的控制（2）。大块非晶合金在较宽温度范围内的变形实验表明，它们的屈服应力几乎与温度无关降到接近零开尔文。为了阐明金属玻璃中位错滑移的扭折控制滑移，进行了计算机模拟研究。本文用逆蒙特卡罗方法和原子间相互作用势对Ni-Nb合金构造了一个真实的二元金属玻璃模型。位错只有在Burgers矢量大于3A时才是稳定的。最小Burgers矢量位错的滑移变形模型是初步假设的，但由于位错滑移的模拟尚未完成，最终的变形模型尚未建立。

It has been clarified that quasicrystals and metallic glasses, both having non-translational symmetry structure, can undergo plastic deformation by slip process. The purpose of the research is to elucidate the microscopic slip deformation mechanisms in these materials of non-translational symmetry, by means of experiments over a wide deformation conditions and of computer simulations(1) As a result of high temperature deformation experiments on various quasicrysmtals, the following facts have been clarified:(a) any quasicrystal can be plastically deformed only above 0.75Tm (Tm: melting point), and the yield stress decreases rapidly with increasing temperature, (b) quasicrystals commonly exhibit pronounced work-softening, and (c) the work-softening is concluded to occur as a result of decreasing activation enthalpy. Based on the computer simulation of dislocations in model quasicrystals, the dislocation glide in a quasicrystal is exerted by a resistance due to a phason wall production s … More uperimposed by that due to a quasiperiodic Peierls potential, and its rate is controlled by kink-pair formation at high temperatures. The deformation behavior is well explained by the model where on the phason-free quasicrystal the dislocation mobility is governed by kink-pair formation at large Peierls potentials, while as phason- defect density increases with plastic deformation it is governed by that at small Peierls potentials(2) Deformation experiments of bulk metallic glasses over a wide temperature range have been shown that their yield stresses are almost temperature independent down to near zero Kelvin. In order to elucidate what kink of dislocation glide governs the slip in metallic glasses, computer simulation studies have been performed. A realistic model binary metallic glass has been constructed by means of the inverse Monte Carlo method and by use of interatomic potentials for a Ni-Nb alloy. It has been classified that dislocation is stable only when its Burgers vector is larger than about 3A. The slip deformation model for the dislocation of the minimum Burgers vector is tentatively assumed, but the final deformation model has not been established yet, since the simulation for the dislocation glide has not been completed Less