Assessment of the influence of layer deposition direction and sequence on anisotropy of mechanical properties in wire laser metal deposition technology for aluminum alloys

MINIATURA 10

Funding Organization: National Science Centre

Project title: Assessment of the influence of layer deposition direction and sequence on anisotropy of mechanical properties in wire laser metal deposition technology for aluminum alloys

Agreement number: DEC-2026/10/X/ST11/00385

Project implementation period: 21.09.2026 r. - 20.09.2027 r.

Principal Investigator: dr inż. Adam Zwoliński

Project value: 49 500,00 PLN

Funds granted for Lublin University of Technology: 49 500,00 PLN

Abstract:  The aim of this research is to systematically evaluate how the direction and sequence of layer deposition influence the mechanical property anisotropy of components manufactured via Wire Laser Metal Deposition (WLMD) using 4XXX series aluminum alloys, specifically AlSi10Mg. The study seeks to identify optimal deposition strategies that minimize anisotropy and to determine the mechanisms behind its formation in relation to additive manufacturing process parameters. WLMD technology is characterized by mechanical property anisotropy resulting from directional solidification and the specific nature of the layer-by-layer build process. This issue is particularly significant for aluminum alloys due to the material's high thermal conductivity, susceptibility to gas porosity, and the microstructure's high sensitivity to the thermal gradients present during the process. A review of the current state of knowledge indicates that most research on anisotropy in additive manufacturing focuses on titanium alloys and steels, whereas aluminum alloys despite growing industrial interest remain far less studied. The lack of systematic research into how deposition strategies affect the degree and nature of mechanical anisotropy in WLMD-processed aluminum alloys limits the method's application in the production of critical components, particularly in the aerospace industry, where isotropic mechanical properties are a key certification requirement. Existing publications focus primarily on optimizing process parameters for geometric quality and defect minimization, without comprehensively addressing the impact of deposition strategies on the distribution of mechanical properties across different directions. The planned research aims to bridge this gap by providing systematic knowledge regarding anisotropy mechanisms and methods for controlling them through the appropriate selection of component-building strategies. The study will be conducted using a laser head equipped with nine blue diode lasers operating in a multi-beam configuration. The material used will be 4XXX series wire (specifically the AlSi10Mg alloy) with a diameter of 1.0–1.2 mm, deposited onto aluminum alloy base plates. The first phase will involve optimizing baseline process parameters (laser power, wire feed rate, head travel speed, and shielding gas flow rate) to achieve a stable deposition process with minimal porosity. The experimental phase will investigate four layer-deposition strategies: unidirectional, 90° cross-hatch (alternating perpendicular layers), zigzag with 45° rotation, and spiral (from the sample perimeter to the center). Specimens for mechanical property testing will be extracted from each sample in three orientations relative to the dominant deposition direction: parallel (0°), perpendicular (90°), and at a 45° angle. The research program will include static tensile testing in accordance with ISO 6892-1 (Rm, Re, A) for each orientation and strategy; Vickers hardness measurements (HV10) per ISO 6507-1 (hardness profiles across successive layers and hardness maps); microstructural analysis (grain size and morphology, layer boundaries, porosity); and the calculation of a mechanical anisotropy index based on the ratio of properties in different directions. The analysis of results will examine the correlation between deposition strategies and the degree of anisotropy, as well as the uniformity of properties throughout the component's volume. This research will provide fundamental insights into the formation of anisotropy during the WLMD process for aluminum alloys and identify optimal deposition strategies to minimize this effect. The findings will enable the development of industrial processing guidelines and indicate directions for future research into the mechanical properties of additive-manufactured components, thereby contributing to the advancement of manufacturing methods within the field of mechanical engineering.