Porous composite with negative thermal expansion obtained by photopolymer additive manufacturing

Akihiro Takezawa, Makoto Kobashi, Mitsuru Kitamura

Research output: Contribution to journalArticlepeer-review

67 Citations (Scopus)


Additive manufacturing (AM) could be a novel method of fabricating composite and porous materials having various effective performances based on mechanisms of their internal geometries. Materials fabricated by AM could rapidly be used in industrial application since they could easily be embedded in the target part employing the same AM process used for the bulk material. Furthermore, multi-material AM has greater potential than usual single-material AM in producing materials with effective properties. Negative thermal expansion is a representative effective material property realized by designing a composite made of two materials with different coefficients of thermal expansion. In this study, we developed a porous composite having planar negative thermal expansion by employing multi-material photopolymer AM. After measurement of the physical properties of bulk photopolymers, the internal geometry was designed by topology optimization, which is the most effective structural optimization in terms of both minimizing thermal stress and maximizing stiffness. The designed structure was converted to a three-dimensional stereolithography (STL) model, which is a native digital format of AM, and assembled as a test piece. The thermal expansions of the specimens were measured using a laser scanning dilatometer. Negative thermal expansion corresponding to less than -1 × 10-4 K-1 was observed for each test piece of the N = 3 experiment.

Original languageEnglish
Article number076103
JournalAPL Materials
Issue number7
Publication statusPublished - 2015 Jul 1
Externally publishedYes

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering


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