Alloy design via additive manufacturing: Advantages, challenges, applications and perspectives

Wire-arc additive manufacturing (WAAM) is a feasible technology for manufacturing of metallic components of medium complexity with a high deposition rate. Manufacturing of aluminum alloys for e.g. structural components of the aero plane fuselage by this technology has been impeded by the unavailability of high-performance alloys with good processability and low susceptibility to hot cracking. Therefore, a novel alloy system has been developed based on the Al-Zn-Mg-Cu system and successfully processed by WAAM without the occurrence of any hot cracks. Heat treatment strategies were developed allowing for optimum mechanical properties. A homogeneous grain structure was observed with few elongated grains. Upon heat treatment, the formation of T phases was verified with a precipitate size in the range of ~10 nm. These are responsible for the observed pronounced age-hardening response of this alloy. An isotropic proof stress of up to ~340 MPa and a fracture strain of up to ~11% are evidence of the high quality of the WAAM deposited material allowing for an extended use of these alloys for advanced applications. Finally, the applicability and processability of the alloy was proven by fabrication of a motorcycle piston.

Wire-arc additive manufacturing of a novel high-performance Al-Zn-Mg-Cu alloy: Processing, characterization and feasibility demonstration

Abstract Metal matrix nanocomposites (MMNCs) become irreplaceable in tribology industries, due to their supreme mechanical properties and satisfactory tribological behavior. However, due to the dual complexity of MMNC systems and tribological process, the anti-friction and anti-wear mechanisms are unclear, and the subsequent tribological performance prediction and design of MMNCs are not easily possible: A critical up-to-date review is needed for MMNCs in tribology. This review systematically summarized the fabrication, manufacturing, and processing techniques for high-quality MMNC bulk and surface coating materials in tribology. Then, important factors determining the tribological performance (mainly anti-friction evaluation by the coefficient of friction (CoF) and anti-wear assessment with wear rate) in MMNCs have been investigated thoroughly, and the correlations have been analyzed to reveal their potential coupling/synergetic roles of tuning tribological behavior of MMNCs. Most importantly, this review combined the classical metal/alloy friction and wear theories and adapted them to give a (semi-)quantitative description of the detailed mechanisms of improved anti-friction and anti-wear performance in MMNCs. To guarantee the universal applications of these mechanisms, their links with the analyzed influencing factors (e.g., loading forces) and characteristic features like tribo-film have been clarified. This approach forms a solid basis for understanding, predicting, and engineering MMNCs’ tribological behavior, instead of pure phenomenology and experimental observation. Later, the pathway to achieve a broader application for MMNCs in tribo-related fields like smart materials, biomedical devices, energy storage, and electronics has been concisely discussed, with the focus on the potential development of modeling, experimental, and theoretical techniques in MMNCs’ tribological processes. In general, this review tries to elucidate the complex tribo-performances of MMNCs in a fundamentally universal yet straightforward way, and the discussion and summary in this review for the tribological performance in MMNCs could become a useful supplementary to and an insightful guidance for the current MMNC tribology study, research, and engineering innovations. 

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Metal matrix nanocomposites in tribology: Manufacturing, performance, and mechanisms

Role of trace nanoparticles in establishing fully optimized microstructure configuration of cold-rolled Al alloy

Recent strides in wire + arc additive manufacturing (WAAM) of aluminum components present unique chances for more enhancements in their properties. More studies were done by controlling manufacturing parameters, the wire properties, arc mode, and applying post-process treatment to regulate the microstructure and mechanical characteristics of the fabricated aluminum parts. In this paper, a wide range of previous late studies has been chosen to research the different attempts leading to an enhancement in the mechanical properties of aluminum components fabricated with WAAM. A discussion of the challenges of applying WAAM for aluminum alloys is also reviewed. The main purpose of this paper is to evolve a detailed understanding of the mechanical characteristics of the deposited aluminum components at various conditions.

Kyle T. Williams

Papers

Welding and Additive Manufacturing with Nanoparticle-Enhanced Aluminum 7075 Wire.

Low Pressure Ignition Testing of a Hybrid SmallSat Motor