A CONSTITUTIVE MODEL FOR THE SUPERPLASTIC MATERIAL ALNOVI-1 INCLUDING LEAK RISK INFORMATION

作者：Snippe Corijn H C^*; Meinders Timo

来源：Steel Research International, 2008, 325-331.

• Superplasticity
• ALNOVI-1
• constitutive model

For some applications, it is important that a formed sheet of material is completely gas tight, therefore it is beneficial to be able to predict whether a formed sheet will be leak tight for gases or not. Superplastic materials show the ability to attain very high plastic strains before failure. These strains can only be reached within a small range of temperature and strain rate. In the case of the aluminium alloy ALNOVI-1 by Furukawa Sky Aluminium, the optimum superplastic behaviour is found at 520 degrees C and at strain rates roughly between 10(-4) to 10(-2) s(-1). Under these conditions, the mechanical behaviour of the material is highly strain rate dependent. This article describes a proposal for the constitutive model of ALNOVI-1, as can be incorporated into an FE code (like a user-defined material UMAT in ABAQUS), in which the leak risk can be implemented, as function of the cavity volume fraction. This will be done in a phenomenological way, using the results of uniaxial tensile and biaxial bulge experiments.

• 出版日期2008