Additive manufacturing of high‐strength polyamide 6 composites reinforced with continuous carbon fiber prepreg

Injection welding is an excellent adhesive‐free bonding method for thermoplastic resins, demonstrating outstanding connection effectiveness. The incorporation of carbon fibers (CFs) significantly enhances the weld shear strength at the injection interface. This study aims to investigate the reinforcement effect of CF‐reinforced thermoplastic composites (CFRTP) during the injection welding process. And explore the influence of the amount of added CFs on the weld shear strength. Polyamide 6 (PA6)/CF composites with CF contents of 10 wt% and 30 wt% were subjected to injection welding for the first and second molding cycles, respectively. It was observed that the reinforcement effects varied considerably depending on the combinations studied. Under the optimal combination and process parameters, the weld shear strength of PA6/CF composites reached 63 MPa, equivalent to 90% of the shear strength (70 MPa) of the original PA6/CF material. Polarized light microscopy and scanning electron microscopy were utilized to analyze the distribution of CFs at the interface and the reinforcing mechanism during tensile fracture. The significance of maintaining uniform CF content during the welding process of PA6/CF composites was emphasized.Highlights Preparation of PA6 composite materials with different carbon fiber contents. Achieving high welding shear strength of composite materials through injection welding. Identified the optimal injection welding conditions to achieve the highest strength. The positive effect of specific fiber distribution on welding strength was analyzed.

Section: Introductionmentioning

confidence: 99%

Interface enhancement and distribution of carbon fibers in injection welding

Wu,

Qiu,

Zhang

et al. 2024

Failure mode analysis and prediction model of additively manufactured continuous carbon fiber‐reinforced polylactic acid

Yang,

Zhou,

Lin

et al. 2024

Carbon fiber‐reinforced composites are widely used in aerospace, rail transportation, and new energy vehicles due to their small specific gravity as well as good mechanical and chemical properties. Additive manufacturing of continuous carbon fiber‐reinforced polymer composites is an innovative composite manufacturing technique. In this paper, bending and shear specimens with different hatch spacing and layer thicknesses were prepared by fused filament fabrication (FFF) technique and subjected to three‐point bending experiments and interlayer shear experiments, respectively. The results showed that the maximum flexural strength and flexural modulus of the fabricated parts were 383.81 MPa and 41.23 GPa, respectively, and the maximum interlayer shear strength was 13.64 MPa. Finally, an optimized criterion for determining fiber kinking, fiber breakage, and matrix damage was proposed by considering in situ strength variations induced by process parameters. This new model was subsequently validated and could provide a method for fracture predicting of additive manufactured carbon fiber‐reinforced composites.Highlights CCFRC parts with different porosities were prepared by adjusting the layer thickness and hatch spacing. The bending and interlaminar shear damage mechanisms of CCFRC fabrications are revealed, and the effects of layer thickness and hatch spacing on their mechanical properties are investigated. Introduction of additive manufacturing factors to optimize failure models for CCFRC parts. Introduction of additive manufacturing coefficients to accurately predict the interlaminar shear strength of CCFRC parts by AM.

Enhanced thermo‐mechanical properties of carbon fiber reinforced thermoresistant polymer, a blend of di‐functional epoxy bisphenol A and a tri‐functional epoxy Tactix 742

Anurangi,

Jayalath,

Rani Senevirathna

et al. 2024

Fiber reinforced polymer composite structures are particularly vulnerable to high temperatures as their strength drastically reduces under elevated temperature conditions. Therefore, it is important to improve the thermal stability of such composite structures to expand their potential range of applications. In this study, the effect of mixing two epoxy monomers, DGEBA and Tactix 742, which are di‐ and tri‐functional, respectively, on the thermal stability of their composites is investigated. The thermo‐mechanical analysis of these composites revealed that the glass transition temperature rose from 123 to 229°C when Tactix 742 is increased from 25% to 75%. The thermal resistance property is attributed to a three‐dimensional crosslink network which is initiated by tri‐functional Tactix 742. However, the higher percentage of Tactix led to a reduction in strength, possibly due to decreased crystallinity and formed amorphous phase material. Subsequently, a tensile strength model was employed to assess the performance at elevated temperatures. It was shown that a matrix with a mix of di‐ and tri‐functional monomers is highly promising for manufacturing thermoresistant polymeric composites with robust mechanical properties, thereby expanding their potential applications across various engineering fields such as civil and construction industries.Highlights A thermoresistant matrix by blending di‐ and tri‐functional epoxy monomers. Improved thermo‐mechanical properties and increased glass transition temperature of fiber reinforced composites. Mechanical performance of carbon fiber reinforced composites at elevated temperatures. Validated a model to estimate the tensile strengths of the composites at elevated temperatures.