Abdulrahman Alrumayh

This chapter examines the tribological performance and wear behavior of Stainless Steel grade (SS316L) and Titanium alloy Ti-6Al-4 V produced by wire arc additive manufacturing (WAAM) and selective laser melting (SLM). It synthesizes published findings on how manufacturing parameters, thermal history, microstructure, hardness, porosity, surface condition, and residual stress influence friction and material loss. Regional variations within WAAM-fabricated components are discussed in relation to layer-by-layer deposition, remelting, heat accumulation, and build location. The chapter also examines the effects of post-processing and wear-test conditions, including applied load, sliding speed, temperature, counterbody material, orientation, lubrication, and testing environment, on the coefficient of friction, wear rate, and wear mechanisms. Common wear-quantification methods, including mass loss, wear-track cross-sectional area, wear volume, and normalized wear rate, are summarized. The presented evidence shows that manufacturing route, material condition, surface preparation, and testing parameters collectively govern tribological behavior. The chapter identifies reporting inconsistencies and research gaps concerning application-specific wear, lubrication, severe environments, transition regions, WAAM-fabricated Ti-6Al-4 V, and links between residual stress and tribological performance across additive manufacturing studies and applications.

Additive manufacturing (AM) of stainless steel has been gaining industry attention in recent years due to the need to manufacture complex steel components. Many sectors stand to benefit from the design flexibility, customization, and rapid production capabilities of AM. However, the industry’s adoption of this technology remains limited due to concerns about the mechanical integrity and reliability of AM products. This experimental study examines the wear and tribological behavior of Wire Arc Additive Manufactured (WAAM) austenitic stainless steel 316L. Pin-on-disk tests were conducted using a 5 mm tungsten carbide ball under dry sliding conditions at normal loads of 1.5 and 2.5 N and sliding speeds between 0.03 and 0.229 m/s. The results showed that the coefficient of friction remained relatively stable at approximately 0.6, while wear volume generally decreased with increasing sliding speed. Lower normal loads resulted in lower wear volume, whereas the wear factor showed only limited sensitivity to the applied load. Optical microscopy revealed a ferrite–austenite microstructure with residual δ-ferrite that contributes to the observed wear behavior. These findings demonstrate the suitability of WAAM-produced 316L stainless steel for tribological applications requiring stable frictional performance.

Wire Arc Additive Manufacturing (WAAM) has emerged as a cost-effective and high-deposition-rate technique for fabricating large-scale metallic components; however, the complex thermal history inherent to the process leads to heterogeneous microstructures that can significantly influence tribological performance. In this study, the dry sliding wear behavior of WAAM-fabricated austenitic stainless steel 308L (SS308L) was systematically investigated using a pin-on-disk configuration. The influence of applied normal load (1.5–15 N) and sliding speed (0.03–0.229 m/s) on wear volume, specific wear rate, coefficient of friction (COF), and tangential force was evaluated. Optical microstructural observations indicated features consistent with a ferritic–austenitic solidification structure, including regions resembling polygonal ferrite, Widmanstätten ferrite, and austenitic dendritic morphologies. Wear results showed that wear volume and cross-sectional area increased monotonically with increasing load, while the effect of sliding speed was comparatively less significant. The specific wear rate remained on the order of 10⁻⁴ mm³/N·m with minor variations across test conditions. The COF decreased with increasing load up to 10 N, followed by a speed-dependent response at higher loads. The findings demonstrate that load is the dominant factor governing wear behavior in WAAM SS308L, while microstructural heterogeneity may contribute to frictional stability and wear resistance. This study provides valuable insight into the structure–tribology relationship of WAAM stainless steels and supports the optimization of process parameters for wear-critical applications.

This paper presents a novel design of a continuum robot driven by electromagnets and springs, offering enhanced precision in multi-degree-of-freedom bending for diverse applications. Traditional continuum robots, while effective in navigating constrained environments, often face limitations in actuation methods, such as wire-based systems or pre-curved tubes. Our design overcomes these challenges by utilizing electromagnetically driven actuation, which allows each segment of the robot to bend independently at any angle, providing unprecedented flexibility and control. The technical challenges discussed emphasize the goals of this work, with the main aim being to develop a motion control system that uses electromagnets and springs to improve the accuracy and consistency of the robot’s movements. By balancing magnetic and spring forces, our system ensures predictable and stable motion in 3D space. The integration of this mechanism into multi-segmented robots opens up new possibilities in fields such as medical devices, search and rescue operations, and industrial inspection. Finite element method (FEM) simulations validate the efficiency of the proposed approach, demonstrating the precise control of the robot’s motion trajectory and enhancing its operational reliability in complex scenarios.