Constitutive equations and computational procedures for modeling nano/micro-scale superplastic forming of bulk metallic glasses

块体金属玻璃纳米/微米尺度超塑性成形的本构方程和计算方法 本构方程 和用于模拟块体金属玻璃的纳米/微米尺度超塑性成形的计算程序。我们将进行以下工作：（a）为非晶态金属制定热-机械耦合、大变形、弹-粘-塑性本构模型，以代表这些材料在高温范围内（高于和低于材料的玻璃化转变温度）的温度和应变率相关的力学行为;以及（B）开发用于纳米/微米热压印的基于有限元的模拟和设计能力。 本研究将（i）有助于阐明这些材料在纳米/微米热压过程中材料特性、加工条件和零件质量之间的关系; (ii)有助于阐明固体和流体材料行为的经典连续力学理论的适用性限制，这些理论与长度尺度无关;并可能导致新理论与材料长度尺度相关性的发展。

Constitutive equations and computational procedures for modeling nano/micro-scale superplastic forming of bulk metallic glasses Abstract The aim of this research program is to develop material constitutive equations and computational procedures for modeling nano/micro-scale superplastic forming of bulk metallic glasses. We will undertake the following tasks: (a) formulate thermo-mechanically-coupled, large-deformation, elastic-visco-plastic constitutive models for amorphous metals to represent the temperature and strain-rate-dependent mechanical behavior of these materials in the high temperature range, both above and below the glass transition temperature of the material; and (b) develop a finite-element-based simulation and design capability for nano/micro-hot-embossing. This study will (i) help elucidate the relationship between material properties, processing conditions, and part quality during nano/micro-hot-embossing of these materials; and (ii) help shed light on the limits of applicability of classical continuum-mechanical theories of solid and fluid material behavior, which are length-scale independent; and perhaps lead to the development of new theories with material length-scale dependence.