Comparison of Experimental and Numerical Study on Superplastic Forming of Rectangular Box Shape using AZ31 Magnesium Alloy Sheet

Super plastic forming has become a feasible process in manufacturing aircraft and automobile parts. Super-plasticity is a property of certain metallic materials which enable them to attain very high elongations (100% and above) without necking under certain conditions. This is assigned to the viscous behaviour exhibited by certain metals and alloys with very fine and stable grain structure at temperatures above half of the melting point. The experimental setup was developed for finding the parametric influences and their effects on super plastic forming. AZ31 Magnesium alloy is most suitable materials for producing more complex shapes using super plastic forming method. The experimental values of pressure, temperature and the thinning, dome height of the super plastically formed specimens were analysed.

Conventional Super Plastic Forming and Multi-attribute Optimization through VIKOR and ANOVA

Super plastic forming is a manufacturing process utilized in the automotive industry like vehicle structures to produce complex geometries of aluminium or magnesium alloy components which cannot be fabricated at room temperature. The technique has proven to be an efficient cost-worthy process in forming various lightweight components for aerospace and medical applications During the process, parameters such as die entry radius, pressure, temperature and material thickness at the sheet die interface greatly influence the metal flow and also depends on product quality. The aim of prsent work is to optimise the conventional super plastic forming process parameters for getting the better quality with proper dimensions of hemispherical cup out of AA2024 sheet. The sheet is placed in a die, which can have a simple to complex geometry depends on the final part to be produced. It is shaped into the hemispherical cup using compressed air. These input process parameters were varied and output parameters such as thickness, maximum height, diameter and minimum forming time of cup were studied and L9 Orthogonal array with a specific end goal to acquire the yield parameters influencing item quality, both VIKOR and ANOVA were assessed.

Development of numerical tool for hybrid manufacturing process for titanium sheet metal forming

The use of titanium in the aerospace industry has grown considerably in recent years in conjunction with the development of composite aircraft. In this way, improving titanium forming has become an important issue for the industry, both for productivity objectives and the ability to deliver basic parts according to the needs imposed by aircraft delivery rates, as well as for cost objectives. Currently, hot forming of titanium parts can be achieved through two processes: Super-plastic forming (SPF) or Hot Forming (HF). The aeronautical industry wanted to develop an innovative process for the manufacture of titanium parts by coupling the HF and SPF processes in order to exploit the advantages of these two technologies. The development of a mixed HF / SPF process will thus not only improve the rates and allow better control of the quality of the formed parts (thickness homogeneity), but also, by allowing forming at lower temperatures, this hybrid process presents a large interest at the energy plan. The study was devoted to the development of a hybrid HF/SPF process, carried out at a common temperature, allowing the “pre-forming” of the part in HF mode and the “calibration” of the part in SPF mode, while respecting a global cycle time compatible with the objectives of the aerospace industry and guaranteeing the quality expected for the final complex part. Improving the performance of the final part requires a development of numerical simulation tool of the forming process. The available simulation tool (ABAQUS/ Standard) must be adapted to define the best simulation strategy according to the simulated parts; moreover, it remains imperative to determine the input data (material behavior laws of titanium alloys) adapted to the cases to be treated (strain rate and process temperature).

Development of Al-Mg Alloys with Different Levels of Mn and Fe for Super-Plastic Forming

New Al-Mg alloys have been developed for super-plastic forming (SPF) based on commercial AA5083/AA5086 alloys, but with an increased Mn content from 0.5 to 1.5 wt.% and a decreased impurity Fe level from 0.25 to 0.05 wt.%.The effects of Mn and Fe levels on super-plasticity have been investigated by high temperature tensile testing of cold rolled H18 sheets at 425 to 525°C with a strain rate of 2×10-3 s-1. The microstructure evolution during different processing stages, grain size and grain size stability were investigated by optical microscopy and scanning electron microscopy. Both Mn and Fe showed a similar and significant contribution to grain size control in recrystallization, but their effect on high temperature sheet formability was different. An increase in Mn level led to an improvement in high temperature tensile elongation, while an increase in Fe content reduced the sheet formability. A new alloy with 1.5 wt.% Mn and 0.05 wt.% Fe, when processed to H18 temper, was able to reach more than 400% tensile elongation at 450 - 500°C with a strain rate of 2×10-3 s-1.