The Effect of Material Properties on the Accuracy of Superplastic Tensile Test

Abstract

Tensile testing is widely used for the mechanical characterization of materials subjected to superplastic deformation. At the same time, it is known that the obtained flow data are affected by specimen geometry. Thus, they characterize the specimen rather than the material. This work provides the numerical analysis aimed to study how the material flow behavior affects the results of tensile tests. The simulations were performed by the finite element method in Abaqus software, utilizing user-defined procedures for calculation of forces acting on the crossheads. The accuracy of tensile testing is evaluated by the difference between the input material flow behavior specified in the simulations and the output one, obtained by the standard ASTM E2448 procedure based on the predicted forces. The results revealed that the accuracy of the superplastic tensile test is affected by the material properties. Even if the material flow behavior follows the Backofen power law, which is invariant for the effective strain, the output stress–strain curves demonstrate significant strain hardening and softening effects. The relation between the basic superplastic characteristics and the tensile test errors is described and analyzed.

Additive Manufacturing of Titanium Alloys: Processability, Properties, and Applications

“…Tang et al [169] investigated the influence of fine powders. As a result, capillary force improved from 8.35 to 16.27 kPa, increasing compression strength from 1.5 to 3.21 MPa.…”

“…Reproduced under the terms of the CC BY license. [169] Copyright 2020, MDPI. such as quick production, the ability to manufacture a wide variety of components with complicated geometry, increased proficiency, fine grain size and phase composition, and decreased energy consumption.…”

“…In 2020, Tang et al [ 169 ] developed Ti6Al4V via BJT. The capillary infiltration of the polymer binder is schematically shown in Figure .…”

“…Capillary infiltration principle based on polymer binder, a) droplets deposited selectively, b) spread of binder solution, c) solution penetrates the powder layer,and d) after heating, the curing film and bridge are developed. Reproduced under the terms of the CC BY license [169]. Copyright 2020, MDPI.…”

Superplasticity and Superplastic Forming

“…The first group of contributions to this special issue faces this precise sub-topic. The contribution by Aksenov Mikolaenko [1] explores a wide range of materials by finite element (FE) simulations and, by doing that, reveals the strong influence of the material properties on the accuracy of results achieved in tensile tests in the superplastic field. In particular, the authors show the potential errors that could be made on the measurements of the strain rate sensitivity and on the strain softening.…”