## 1 Introduction  
The aeronautical industry has long been one of the leading players in the development and implementation of new high-added-value, advanced materials [1]. The big margin on manufacturing cost compared to the material and performance has made difficultly shaped components and the extensive use of trial and error methodologies in the manufacturing process characteristic of this sector. Clear examples to reduce that effort are the work of [PERSON] and [PERSON] [2] on stretch forming and the work of [PERSON] et al. [3] on Ti-alloy tube bending. Global mobility trends, together with tightening of the economy, have led to a departure in aircraft manufacturing from big planes (e.g., A380 and Boeing 747) to the current trend of a large number of smaller aircraft (e.g., A320 or smaller) [4]. This change in product volume has increased the importance of manufacturing costs relative to overall costs within the sector. Driven by such change, numerous aeronautical component producers have been exploring the use of automotive-based technologies to reduce manufacturing costs, while maintaining quality [5]. In this regard, stamping (or deep drawing) is one of the most cost-effective manufacturing processes for sheet metal components used in aircraft fuselage and engines [6]. The migration from traditional forming processes to mass production stamping base processes has given rise to various issues due to the high springback. Traditionally, aeronautical components are characterized by a very streamlined and small curvature design and are manufactured with high- or very-high-strength material. These two features increase the springback after forming exponentially [7]. To address these issues, thermal treatments (TTs) are commonly employed in an effort to reduce residual stresses or improve formability. The sector is in need of high-volume manufacturing processes that allow for intermediate TTs. Previous research demonstrated the importance of finite element methods in efficient design and optimization of cold stamping processes [7]. In recent years, much effort has focused on the modelling of aeronautical-grade stamping operations [8]. However, due to the innate secrecy of the sector, little published information on this topic is available. In the case of Inconel 718, some information is available on the elasto-plastic modelling of stamping operations. For example, [PERSON] et al. [9] studied the ductile fracture of bulk Inconel 718, and [PERSON] et al. [10] modelled the behaviour of the material at intermediate temperatures using kinematic hardening models. The most comprehensive work on modelling Inconel 718 material was published by [PERSON] et al. [11]. They analysed and modelled the springback behaviour of Inconel 718 used in the aerospace industry. In their hardening model, they assumed constant elastic behaviour, with a Hill48 yield function and a Bauschinger effect. Later research proved that a decrease in the apparent elastic modulus had a critical impact on springback simulations [12]. Other studies showed that this phenomenon, which appeared to be related to dislocation pile-up [13], increased springback after forming [14]. The friction conditions during draw-in of the material were shown to be equally important [7]. To our knowledge, there are no studies on the impact of intermediate annealing TTs on material behaviour. Therefore, in terms of aeronautical requirements, it is not possible to accurately predict the forming behaviour and subsequent springback of components of Inconel 718 after intermediate annealing TTs. In the present study, the behaviour of Inconel 718 material in its as-received (AR) state and post-stretching TT (PSTT) state was analysed and modelled. First, potential microstructural changes due to the annealing TT were analysed. Second, the elasto-plasticity behaviour of the material (i.e., elastic behaviour, plastic yielding, hardening and necking limit) was characterized under both AR and PSTT conditions.