Superplastic Process Modeling and Material Characterization Study of Selected Metal Alloys

该项目的主要目标是为选定的超塑性板材压力(吹塑)成形操作开发数学过程模型。超塑性金属的率敏感特性决定了必须控制其成形过程中的应变速率，以优化其成形特性。因此，一个受控的加压时间表对于精确的过程控制是必要的。模型的目的是预测：(A)保持最佳成形条件的压力-时间加载循环，即最大塑性和最小空化，以及(B)成形零件中的厚度分布。本构方程将在单轴和双轴条件下实验建立，作为模型的输入。此外，还将研究抑制汽蚀的静水压力要求。将研究作者开发的一种新的膜单元数值方法和非线性有限元方法。测试的合金包括精选的铝锂合金以及6A1-4V钛。

The primary objective of this project is to develop mathematical process models for selected superplastic sheet metal pressure (blow) forming operations. The rate-sensitive properties of superplastic metals make it imperative that the strain-rate during forming be controlled to optimize their forming charateristics. A controlled pressurization schedule is thus necessary for accurate process control. The purpose of the models is to predict: (a) the pressure-time loading cycle to maintain optimum forming conditions, i.e., maximum ductility and minimum cavitation, and (b) the thickness distribution in the formed part. Constitutive equations will be developed experimentally under both uniaxial and biaxial conditions for input to the models. Hydrostatic pressure requirements to suppress cavitation will also be studied. A new numerical procedure using membrane elements developed by the authors will be investigated as well as non-linear finite element methods. The alloys tested include selected Aluminum-Lithium alloys as well as 6A1-4V Titanium.