Increased fracture toughness of additively manufactured amorphous thermoplastics via thermal annealing

POLYMER

卷:144

Article

Hart, Kevin R.¹  Dunn, Ryan M.¹  Sietins, Jennifer M.¹  Mock, Clara M. Hofmeister²  Mackay, Michael E.³  Wetzel, Eric D.¹ 

[1] US Army, Res Lab, Mat & Mfg Sci Div, Aberdeen Proving Ground, MD 21005 USA

[2] Oak Ridge Inst Sci & Educ, Belcamp, MD 21017 USA

[3] Univ Delaware, Dept Chem & Biomol Engn, Newark, DE 19716 USA

关键词: Additive manufacturing;    Fracture mechanics;    Interface healing;   

DOI  :  10.1016/j.polymer.2018.04.024

来源: Elsevier

【 摘 要 】

Polymeric structures fabricated using Fused Filament Fabrication (FFF) suffer from poor inter-laminar fracture toughness. As a result, these materials exhibit only a fraction of the mechanical performance of those manufactured through more traditional means. Here we show that thermal annealing of confined structures manufactured using the FFF technique dramatically increases their inter-laminar toughness. Single Edge Notch Bend (SENB) fracture specimens made from acrylonitrile-butadienestyrene (ABS) feedstock were isothermally heated in a supporting fixture, post-manufacture, across a range of times and temperatures. Fracture testing was then used to quantify the changes in inter-laminar toughness offered by annealing through measurements of the Mode I critical elastic-plastic strain energy release rateik. Under the most aggressive annealing conditions, the inter-laminar toughness increased by more than 2700% over the non-annealed baseline material. Void migration and aggregation during the annealing process was analyzed using X-ray tomography and provides insight into the toughening mechanisms. Time-scales of reptation and polymer mobility at the interface during annealing are also modeled and agree with fracture experiments. Published by Elsevier Ltd.

【 授权许可】

Free