Strategy towards tailored high-performance metal materials for additive manufacturing

Karg M, Ahuja B, Schmidt M (2015)


Publication Language: English

Publication Type: Conference contribution

Publication year: 2015

Event location: Fraunhofer IWS Dresden Winterbergstr. 28 01277 Dresden DE

URI: http://www.iws.fraunhofer.de/en/events/archive_2015/additive_manufacturing_2015/proceedings.html

Abstract

Many engineering materials have not only been fine-tuned to fulfill requirements of products, but also those of production. Prominent examples are primary forming processes like casting or forging. However, this has not been the case for joining techniques such as fusion welding, which exposes materials to characteristically high spatial temperature gradients and cooling rates in time. Instead, workarounds such as the compensation of joint weaknesses through adapted geometry design, changing material composition in the fusion zone with fillers or sophisticated processing technologies have been developed. These are often costly and time-consuming. Additive Manufacturing (AM) combines characteristics of both joining as well as primary forming: Complex near-net-shape geometries are created by joining shapeless matter.
In AM of polymers, a paradigm has been evolving to combine certain process and system technology with specific materials. Only few matching combinations of this triplet were able to reach commercial and industrial success. In metal AM processes like metal laser beam melting in powder bed (LBM) and laser metal deposition with powder injection (LMD), material is fused through the liquid phase – closely related to conventional welding. The apparently predominant and without doubt successful approach to push the boundaries of metal AM has been to adapt processes and machines to live up to materials, which are defined by applications.
We want to put forward the question, if unexpected potentials might be unleashed by complementing AM research with a different approach. Maybe characteristics of metal AM, which are often perceived as restrictions can be converted into real strengths. Locally restricted cyclic melting with rapid solidification and subsequent multiple re-heating are defining qualities of metal AM. Unlike in traditional powder metallurgy, no bulk mass of powder is processed but thin layers in LBM, or gas fluidized streams in LMD. A top-down strategy is suggested: The first step would be to abstract, refine and compare features that determine the processibility of materials established in AM. This improved in-depth understanding could be used to choose and design alloys, powders and composites specifically for AM. Results might be materials which are less apt for conventional processing. Provided they prove suitable in experiments, such materials might be iteratively improved and then considered for the latest stage of implementation in industrial use cases.
Examples for high-performance materials from ongoing AM research at the Institute of Photonic Technologies (LPT) and the mechanisms behind are analyzed comparatively on a high level. They encompass high strength aluminium wrought alloys [1], metal matrix composites [2] and amorphous metals. The latter in fact need high solidification rates in order to reach desired properties, which limits their suitability for conventional processes.
 

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APA:

Karg, M., Ahuja, B., & Schmidt, M. (2015). Strategy towards tailored high-performance metal materials for additive manufacturing. In Proceedings of the 1st International Symposium on Additive Manufacturing, IWS Dresden. Fraunhofer IWS Dresden Winterbergstr. 28 01277 Dresden, DE.

MLA:

Karg, Michael, Bhrigu Ahuja, and Michael Schmidt. "Strategy towards tailored high-performance metal materials for additive manufacturing." Proceedings of the 1st International Symposium on Additive Manufacturing, IWS Dresden, Fraunhofer IWS Dresden Winterbergstr. 28 01277 Dresden 2015.

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