D.L. Sun

Bio: D.L. Sun is an academic researcher from Harbin Institute of Technology. The author has contributed to research in topics: Microstructure & Hypervelocity. The author has an hindex of 10, co-authored 28 publications receiving 470 citations.

In situ characterization of the deformation and failure behavior of non-stochastic porous structures processed by selective laser melting

Abstract: Cellular materials are promising candidates for load adapted light-weight structures Direct manufacturing (DM) tools are effective methods to produce non-stochastic structures Many DM studies currently focus on optimization of the geometric nature of the structures obtained The literature available so far reports on the mechanical properties but local deformation mechanisms are not taken into account In order to fill this gap, the current study addresses the deformation behavior of a lattice structure produced by selective laser melting (SLM) on the local scale by means of a comprehensive experimental in situ approach, including electron backscatter diffraction, scanning electron microscopy and digital image correlation SLM-processed as well as heat treated lattice structures made from TiAl6V4 alloy were employed for mechanical testing It is demonstrated that the current approach provides means to understand the microstructure-mechanical property–local deformation relationship to allow for optimization of load adapted lattice structures

Selective laser melting additive manufactured Inconel 718 superalloy parts: High-temperature oxidation property and its mechanisms

Abstract: This work presented a comprehensive study of high-temperature oxidation behaviors and mechanisms of Selective laser melting (SLM) processed Inconel 718 superalloy parts using different methods including isothermal oxidation testing, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The experimental results revealed that the oxidation process of the tested parts processed at a lower volumetric laser energy density experienced the severe spallation. On reasonably increasing the applied volumetric laser energy density, the oxidation kinetics of the as-produced parts obeyed a parabolic law, exhibiting the significantly improved oxidation resistance performance. The constitutional phases within the oxidation film were identified and the corresponding formation mechanisms were elucidated in detail according to the thermodynamic principles. The cross-sectional morphologies of oxidized Inconel 718 parts indicated that the oxidation microstructure mainly consisted of an external oxidation layer and an internal oxidation zone. The oxidation process was controlled by the outward diffusion of oxide forming elements and inward penetration of oxygen, by which the interaction mechanisms between the microstructures and internal oxidation zones were clarified. On the basis of the experimental results and theoretical analyses, the physical oxidation mechanisms were accordingly established to illustrate the oxidation behaviors of SLM-processed Inconel 718 parts at elevated operative temperatures.

Development of metal-matrix composites from industrial/agricultural waste materials and their derivatives

Abstract: In this contribution, authors present a review on the state-of-the-art in the utilization of industrial and agricultural waste materials for the development of metal–matrix composites (MMCs), providing, through the judicious analysis of an ample and varied references source – from the oldest to the newest ones – an insight into the challenges and opportunities for the exploitation to their full potential. In addition to its topicality, the novelty of this contribution lies in the presentation of key statistical, technical, and property-related information of a comprehensive variety of waste materials classed into two main groups, namely, fly ash reinforced MMCs and MMCs derived from other waste materials. Although fly ash has been exploited in a broad range of applications, the attention paid for its use in the development of MMCs seems to be insufficient. A purposely designed chart helped to pinpoint the more demanding and profitable applications of fly ash, and establish strategic opportunity ar...

Cenosphere filled aluminum syntactic foam made through stir-casting technique

Abstract: Cenospheres in the range of 30–50 vol.% were used as space holders for making syntactic aluminum foam having density 1.5–1.9 gm/cc using stir-casting technique. The synthesized syntactic foam (SF) was characterized in terms of microstructures, hardness and compressive deformation behaviour. It was noted that the SF behaves like a high strength aluminium foam under compressive deformation exhibiting flat plateau region in the stress–strain curves. The plateau stress of SF decreases with cenosphere volume fraction vis-a-vis porosity following a power law relationship. But, the densification strain increases linearly with cenosphere volume fraction.