Compression Behaviour of Wire + Arc Additive Manufactured Structures

Abstract

Increasing demand for producing large-scale metal components via additive manufacturing requires relatively high building rate processes, such as wire + arc additive manufacturing (WAAM). For the industrial implementation of this technology, a throughout understanding of material behaviour is needed. In the present work, structures of Ti-6Al-4V, AA2319 and S355JR steel fabricated by means of WAAM were investigated and compared with respect to their mechanical and microstructural properties, in particular under compression loading. The microstructure of WAAM specimens is assessed by scanning electron microscopy, electron back-scatter diffraction, and optical microscopy. In Ti-6Al-4V, the results show that the presence of the basal and prismatic crystal planes in normal direction lead to an anisotropic behaviour under compression. Although AA2319 shows initially an isotropic plastic behaviour, the directional porosity distribution leads to an anisotropic behaviour at final stages of the compression tests before failure. In S355JR steel, isotropic mechanical behaviour is observed due to the presence of a relatively homogeneous microstructure. Microhardness is related to grain morphology variations, where higher hardness near the inter-layer grain boundaries for Ti-6Al-4V and AA2319 as well as within the refined regions in S355JR steel is observed. In summary, this study analyzes and compares the behaviour of three different materials fabricated by WAAM under compression loading, an important loading condition in mechanical post-processing techniques of WAAM structures, such as rolling. In this regard, the data can also be utilized for future modelling activities in this direction.

Description of anisotropic material response of wire and arc additively manufactured thin-walled stainless steel elements

“…These barriers relate, to a large extent, to the scarcity of test data on the mechanical properties and structural performance of additively manufactured materials [12,13,14]. In light of this, there has recently been a growing number of research groups investigating the microstructural and mechanical properties of different WAAM materials, including lowalloy steels [15,16,17,18,19] and various stainless steel alloys [20,21,22,23,24,25,26,27]. The aforementioned studies have revealed a degree of anisotropy in the behaviour of WAAM stainless steel material, i.e.…”

Design of a Cost-Effective and Statistically Validated Test Specification with Selected Machine Elements to Evaluate the Influence of the Manufacturing Process with a Focus on Additive Manufacturing

“…The other results confirm the distribution of the tooth root and the bending tests and thus the determined general manufacturing factors for the additive processes. The material-dependent anisotropic behaviour of the compression specimens manufactured with the WA-DED method described by Abbaszadeh can consequently be confirmed [23]. Furthermore, Longhitano et al determined anisotropic mechanical properties for L-PBF manufactured components [22].…”

“…Abbaszadeh et al analysed the results of the compression behaviour of WA-DED structures for different materials. They showed material-dependent anisotropic behaviour [23]. Bambach et al examined the hot forming behaviour of Ti6Al4V made by AM.…”

“…Deng et al (2019) performed a similar study and made a distinction between specimens that underwent heat treatment at 650 • C and those that did not [30]. In their study [31], Davies et al conducted comparable investigations wherein they analysed samples taken both horizontally and vertically in their original state, as well as after undergoing heat treatments at 700 • C and 900 • C. Komorasamy et al accomplished a comparative analysis of the behaviour of notched bar impact specimens extracted horizontally and vertically with respect to the direction of exposure as per DIN EN ISO 148 on Inconel 718 [23]. Yasa et al examined the notched bar impact strength of L-PBF produced parts made of 316L, Ti6Al4V, and maraging steel.…”