Special Issue on Additive Manufacturing with Metals

Additive manufacturing (AM) with metals is currently one of the most promising techniques for 3D-printed structures, as it has tremendous potential to produce complex, lightweight, and functionally-optimized parts. The medical, aerospace, and automotive industries are some of the many expected to reap particular benefits from the ability to produce high-quality models with reduced manufacturing costs and lead times. The main advantages of AM with metals are the flexibility of the process and the wide variety of metal materials that are available. Various materials, including steel, titanium, aluminum alloys, and nickel-based alloys, can be employed to produce end products. The objective of this special issue is to collect recent research works focusing on AM with metals. This issue includes 5 papers covering the following topics: ===danraku===- Powder bed fusion (PBF) ===danraku===- Directed energy deposition (DED) ===danraku===- Wire and arc-based AM (WAAM) ===danraku===- Binder jetting (BJT) ===danraku===- Fused deposition modeling (FDM) This issue is expected to help readers understand recent developments in AM, leading to further research. We deeply appreciate the contributions of all authors and thank the reviewers for their incisive efforts.

Study on the Microstructure and Wear Mechanism of Grain-Refined Zinc-Aluminum Alloy

Some low-titanium aluminum alloys were prepared and the effect of titanium elements on microstructure and wear property of zinc-aluminum alloy was investigated. The test results showed that addition of titanium is an effective way to refine the grain size of zinc-aluminum alloy. As the titanium content is 0.04 wt%, the grain size becomes to be a minimum value. The wear resistance is also improved with the decrease in the grain size. This can be attributed to the grain boundary strengthening of the test alloys leading to strain hardening. SEM photomicrographs of the worn surfaces shows that the test alloys with and without grain refinement exhibit similar wear mechanism. However, the grain-refined sample of the alloy exhibited a more stable friction coefficient than that of the untreated ones under the same test conditions.