High-temperature tensile behavior of AlSi7Mg parts built by LPBF under high-productivity conditions

As additive manufacturing of metals gains traction for demanding applications, more comprehensive material cards covering mechanical response across a broader spectrum of operating conditions are needed. The integration of additive manufacturing into industries that rely on aluminum alloys, notably automotive and aerospace, underscores the imperative of a profound comprehension of how these materials respond to mechanical loading at elevated temperatures. Such insights are not only important for powertrain components but also for parts that combine structural and functional purposes, such as heat exchangers. At the same time, automotive applications need to target the production of large parts with sufficiently high productivity. This study addresses the intricate interplay between microstructural evolution, plastic deformation and mechanical response of AlSi7Mg parts fabricated by laser powder bed fusion under high-productivity conditions, spanning a testing temperature range of 25-300 degrees C. Above 150 degrees C, a significant decrease in proof and tensile strength is measured, accompanied by localized necking and the formation of dimples on the rupture surfaces. At 300 degrees C, the pronounced plasticization leads to yielding and failure at stress values 30-40% lower than at room temperature, with triple ductility. Work-hardening coefficients were calculated to describe the plastic regime. Furthermore, an investigation into density, hardness, microstructure, and fracture surfaces was conducted to corroborate the mechanical response. The outcomes enabled the quantification of mechanical property variations across the 6 temperature intervals, thereby constructing a map that empowers industry to unlock the full potential of additive manufacturing aluminum alloys.