Material Deposition Rate Research Articles

Electro-discharge deposition of zinc powder on 316L stainless steel: Synthesis, deposition rate, and characterization

This study investigated the potential of powder-mixed electrical discharge machining (PM-EDM) to deposit metallic powder, specifically zinc powder, on 316L stainless steel (316L SS). This study aimed to evaluate the effect of zinc (Zn) deposition on 316L SS for oil and gas application. Minitab 19 software was employed to design the experiments using screening DOE option and to analyse and model the results through screening response optimiser from Minitab 19 software. Surface morphology, microstructure and coating thickness were examined through field-emission scanning electron microscopy (FESEM) and scanning electron microscope (SEM). The results suggested an improvement in the coating thickness with an increase in powder concentration and discharge current. An average coating thickness of 91.47 μm was achieved in samples fabricated at 20 g/L powder concentration. X-ray diffraction analysis revealed the formation of hard carbides, such as Cr3C2 and TiC, on the PM-EDMed 316L SS surface. Further characterisation through energy-dispersive X-ray spectroscopy confirmed the deposition of both the tool electrode and Zn powder particles. The adhesion test confirmed that all specimens failed under 100% adhesive failure. The hydrophobicity analysis confirmed that the coated surfaces are hydrophobic. Significant improvement has been established for microhardness, wear resistance and corrosion performance. Screening results revealed that discharge current, pulse-on time, and powder concentration were the most significant parameters. The average predicted errors of 2.055%, 6.782%, and 2.396% for material deposition rate, tool wear rate, and surface roughness were achieved, respectively. These affirmed the excellent reproducibility of the model developed. This study presents a methodology for the formation of carbide- and oxide-based coatings specifically for oil and gas applications (flanges and connectors).

Effect of TaC content on microstructure and wear behavior of PRMMC Fe-TaC coating manufactured by electrospark deposition on AISI304 stainless steel

The Fe-TaC coatings on stainless steel by electrospark granule deposition in an anode mixture of iron granules and tantalum carbide powder were first obtained. The material deposition rate on the substrate increased with the TaC powder concentration growth in the anode mixture, facilitating the initiation of electrical discharges. X-ray analysis of deposited coatings shows the presence of the TaC, γFe, and αFe phases. The tantalum carbide concentration grows with an increase in the content of TaC powder in the anode mixture, from 2.4 to 14.8 vol%. The dependence of the wear rate of coatings on the concentration of tantalum carbide in the anode mixture had a parabola form, with a minimum of 5 vol%. However, with a further increase in the TaC concentration in the anode mixture, the wear rate of the coatings monotonically increased due to spalling of TaC grains due to a deficiency of the metal binder.

Meso-level surface modification of Hastelloy C276 by WS2 powder mixed electrical discharge alloying process through micro-EDM setup

The present research provides a rigid, wear-resistant lubricating localized layer on Hastelloy C276 (HC 276) surface at meso level by tungsten disulphide (WS2) powder suspended electrical discharge alloying (EDA) process through micro-electrical discharge machining (μ-EDM) setup. The performance characteristics of the coated surface were evaluated in terms of material deposition rate (MDR), surface morphology, surface roughness (Ra, Rz and Rq), recast layer thickness (RLT), compositional analysis, micro-hardness & indentation depth, wear test and water contact angle analysis. Maximum MDR has been achieved at 15 g/L WS2 concentration and 80 V of gap voltage whereas The RLT varies from 6.87 μm to 18.91 μm and is enhanced with the increase in WS2 concentration. The critical surface characterization confirms higher WS2 concentration reduces the crater dimensions and the presence of micro-cracks and micro-voids on the coated surface. The surface roughness has been increased with the gap voltage and capacitance, whereas higher WS2 concentration provides lower surface roughness. X-Ray diffraction analysis (XRD) confirms the presence of hard and wear resistance phases like WC, WO3, ZnO, and MoO2 on the coated surface. Energy-Dispersive X-Ray Spectroscopy (EDS) analysis along with elemental mapping justifies tool, dielectric materials, and powder particles migration on the coated surface. The micro-hardness of the coated surface (402 HV to 1166 HV) is enhanced by 3–4 times compared to the base material (299 HV) whereas the indentation depth has been reduced with the rise in WS2 concentration and lies within the RLT of the coated surface. The wear rate of the WS2 coated surface is drastically reduced compared to the base material with a lower value of coefficient of friction (COF). The coated surface became hydrophobic in nature with a contact angle of 109.6° compared to the hydrophilic base HC 276.

Experimental Studies on the Anisotropic Fatigue Behaviour of IN718 Fabricated via Wire Arc Additive Manufacturing

Wire and arc additive manufacturing (WAAM) offers promise in creating large complex structures due to its flexibility and high material deposition rates. The nickel-based alloy IN718 is favoured for WAAM due to its weldability and compatibility. However, WAAM can introduce issues like anisotropic grain structure, porosity, and residual stresses which can lead to directional variations in tensile, fatigue, and fracture behaviour. This paper studied the WAAM process of IN718, utilising cold metal transfer (CMT). The optimised CMT-WAAM parameters for IN718 were identified to as a wire feed speed of 8–10 m/min and a torch travel speed of 0.5–0.7 m/min, resulting in stable deposition and minimal defects. Nevertheless, columnar grain structures were observed in the build direction (BD), with coarse grains in the wall-length direction (WD). This anisotropic microstructure coupled with stress concentrators, contributes to the directional dependence observed in tensile properties, fatigue endurance, and crack growth. The investigation revealed superior ductility in the BD compared to the WD. Interestingly, the fatigue endurance testing showed a longer life in the WD compared with the BD, attributed to stronger stress concentrators in the BD specimens. However, when examining a cracked specimen, the fatigue crack propagated faster in the WD rather than the BD.

Development of concurrent multi wire feed mechanism for WAAM-TIG to enhance process efficiency

A novel multi wire feed mechanism has been introduced and investigated for tungsten-inert-gas-based wire arc additive manufacturing (WAAM-TIG) method to minimise the dependency of wire feed direction. The concurrent three wire feed mechanism mounted 120° apart around the TIG torch was developed by employing three independent wire feeders, and an integrated effect of front-back-side feeding minimised the dependency of the wire feeding direction on the deposited bead. The mechanism was compared with the single wire feed, and geometrical uniformity, material deposition rate and overall specific energy requirements were found to improve by ∼26%, ∼66% and ∼56%, respectively, with good arc-stability.

Assessing the pros and cons of wire-arc additive manufacturing for material production

A promising new method for mass-producing metal components and structures for a range of industries, including shipbuilding, automotive, aviation, and other technical sectors, is wire arc additive manufacturing (WAAM). Additive manufacturing (AM) called 3D printing, it is a disruptive manufacturing technique that starts with digital design data and manufactures products layer by layer. WAAM has been utilized to create parts from a variety of materials, such as alloy wires based on aluminium (Al), titanium (Ti) and nickel. This review article focuses on the most important facets of the WAAM process, including the technology utilized, the drawbacks encountered, the steps taken during and after the process, the tools used to monitor the process, the gases involved, and the materials. The comparison of WAAM with other additive manufacturing technologies is also emphasized in the article. Moreover, it compares and analyses several WAAM techniques, including plasma arc welding (PAW), gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW) in terms of material deposition rate, the method GMAW have higher material deposition rate when compared to other approach. Material manufacturing using WAAM has great potential. The accuracy of the manufacturing and smoothness of WAAM-made parts can be enhanced in the future to better suit tight-tolerance uses.

Parametric study on surface modification of Al-7075 alloy using electric discharge coating

This work investigates the surface modification of Al-7075 alloy using a copper-multi-walled carbon nanotube powder metallurgical green compact tool in the electric discharge coating process. The effect of input parameters such as compact load, peak current ( Ip), and pulse on-time ( Ton) on material deposition rate and surface roughness ( Ra) has been investigated. The process parameters are optimised using the teaching learning-based optimisation algorithm. Maximum material deposition rate of 0.62 mg/min with minimum Ra of 3.00 µm has been achieved at compact load of 6 tons, Ip of 2.5 A, and Ton of 1000 µs. The field emission scanning electron microscopy images show smooth surface generation at low Ip and compact load settings. Characterisation using different techniques confirms the presence of tool materials on the modified surface. The microhardness test of the modified surface exhibits a higher hardness value of 2.70 times than that of the substrate material.

Bead geometry prediction and optimization for corner structures in directed energy deposition using machine learning

Wire Arc Additive Manufacturing as a Directed Energy Deposition technology has disruptive potential for modern manufacturing. The technology comes with the flexibility and material efficiency of additive manufacturing processes while mitigating the disadvantages through high material deposition rates and high energy efficiency. However, the prevalence of the technology is inhibited by its geometrical inaccuracy and the large induced residual stresses. This work tackles the former problem by capturing the process parameter-geometry relationship using Machine Learning. To do so, multiple mild steel welding beads with varying shape features like corner angles are printed using a Metal Inert Gas welding machine attached to an industrial robot. The cross-sectional profile of the printed beads is measured using a point laser sensor and correlated through a Multilayer Perceptron to input features such as travel speed, wire feed speed, and shape features. By incorporating varying corner angles, a holistic model, not limited to geometry prediction of straight beads only, is trained. Using the model, excess material at the inner angle of corners determined by the overlapping regions of the two adjacent beads can be predicted. By generating a database of possible bead shapes an inverse algorithm that suggests welding parameter combinations that yield a smooth bead shape at the corner is created, thus enabling improvement of the overall accuracy of the Wire Arc Additive Manufacturing process.

System identification and closed-loop control of laser hot-wire directed energy deposition using the parameter-signature-quality modeling scheme

Hot-wire directed energy deposition using a laser beam (DED-LB/w) is a method of metal additive manufacturing (AM) that has benefits of high material utilization and deposition rate, but parts manufactured by DED-LB/w suffer from a substantial heat input and undesired surface finish. Hence, regulating the process parameters and monitoring the process signatures to control the final quality during the deposition is crucial to ensure the quality of the final part. This paper explores the dynamic modeling of the DED-LB/w process and introduces a parameter-signature-quality modeling and control approach to enhance the quality of modeling and control of part qualities that cannot be measured in situ. The study investigates different process parameters that influence the melt pool width (signature) and bead width (quality) in single and multi-layer beads. The proposed modeling approach utilizes a parameter-signature model as F1 and a signature-quality model as F2. Linear and nonlinear modeling approaches are compared to describe a dynamic relationship between process parameters and a process signature, the melt pool width (F1). A fully connected artificial neural network is employed to model and predict the final part quality, i.e., bead width, based on melt pool signatures (F2). Finally, the effectiveness and usefulness of the proposed parameter-signature-quality modeling is tested and verified by integrating the parameter-signature (F1) and signature-quality (F2) models in the closed-loop control of the width of the part. Compared with the control loop with only F1, the proposed method shows clear advantages and bears potential to be applied to control other part qualities that cannot be directly measured or monitored in situ.

Experimental analysis of surface integrity in electro-discharge coating process

Utilising electro-discharge machining, powdered metallurgical tool materials are applied to coat the surface pattern-wise. The tool undergoes a thorough blending process followed by hydraulic pellet press. Essential evaluations encompass the determination of material deposition rate, tool wear rate, surface roughness, microhardness, layer thickness and wear rate. Characterisations confirm the presence of tool constituents, provide insights into its constituent's composition and reveal the formation of tungsten carbides on the uppermost surface of the deposit. Significantly, a substantially higher deposition rate of 4.9 mg/min is achieved when a compact load of 10 tons and a peak current of 2.5A are applied. Notably, the top surface exhibits a microhardness of 330.5 HV, while the base material maintains a hardness level of 98.7 HV. The maximum thickness of the deposited layer reaches 293.68 μm under identical conditions. These hard materials serve to mitigate the specific wear rate effectively.

Experimental investigations and optimization of process variables of electro discharge coating process for Al-7075 alloy: a hybrid MCDM approach

The present study aimed to improve and assess the electrical discharge coating (EDC) factors with aluminium 7075 alloy as a substrate. The results of input variables like current, composition, and compaction load on EDC responses, including material deposition rate (MDR), tool wear rate (TWR), and surface roughness (Ra) were studied. Taguchi’s L9 experiment design was employed with GRA (grey relational analysis), ARAS (Additive Ratio Assessment), and preference value (Ki) was measured. The experiments determined the best parametric setting for more MDR, less TWR, and less Ra. The level of contribution of the process parameters to the response was evaluated by a statistical test known as ANOVA, wherein current appeared as the most noteworthy parameter, followed by composition and compaction load. The results of GRA and ARAS were compared with a prominent MCDM method known as TOPSIS, which substantiated the outcomes of both methods. Successfully attained rates for material deposition, tool wear, and average surface roughness were 0.385 mg/min for material, 4.37 mg/min for tool wear, and 2.101 µm for surface roughness. Finally, a sensitivity study is used to validate the hybrid model’s constancy with a strong correlation. The topography of the deposited surface was analyzed by SEM, wherein base material, deposition, and interface were distinctly visible with the occurrence of a few micro-cracks. The XRD contour of the coating exhibited peaks of Al, Al2Cu, Cu, and SiC. Additionally, the pin-on-disc wear result yielded a substantial drop in the wear of the coated samples as compared to the substrate material.

PROCESS OPTIMIZATION OF ELECTRO-SPARK DEPOSITION USING LASER POWDER BED FUSION PROCESSED AlSi10Mg TOOL ELECTRODE THROUGH BOX-BEHNKEN DESIGN

Several researchers have recently expressed interest in additively manufactured electrodes for machining and surface modification applications. The additively manufactured AlSi10Mg tool electrode is one of the promising candidate materials for non-conventional processes. This research investigates the process parameters of laser powder bed fusion (L-PBF) processed AlSi10Mg tool electrodes for the electro-spark deposition process (ESD). The selected deposition parameters, namely, peak current (Pc), pulse-on time (Pon) and deposition time (DT) with various levels and experimentation, are based on the box-behnken design (BBD) of the response surface methodology. The deposition was carried out to analyze the output responses of material deposition rate (MDR), additive tool wear rate (ATWR) and surface roughness (SR). The multi-objective optimization was performed to minimize the ATWR and SR and maximize the MDR. The optimized ESD parameters of Pc = 6 A, Pon = 20[Formula: see text]s, and DT = 5 min were found with predicted responses of MDR = 0.019 mg/min, ATWR = 0.095 mg/min and SR = 3.86 [Formula: see text]m. The deposited surface witnessed the formation of debris, microcracks, and a solidified surface with a dark region and accumulated worn debris that has an elongated and flat shape. The workpiece substrate was exposed to a significant amount of additive tool electrode material (Si, Al, O, Mg, S), and different intermetallic ([Formula: see text] Si) 0.148, Al2O3, and Al2S3 formations have been recognized. This finding corroborates the efficient usage of L-PBF AlSi10Mg electrodes for ESD processes.

Dynamic Extrusion Control in Spot Deposition Modeling for Porous 3D Clay Structures

The dynamic state of the viscous clay in Liquid Deposition Modeling (LDM) often leads to discrepancies between the digital model and the resulting physical object. This emergent behavior can be harnessed to produce complex physical structures that would not be possible with other methods. This study takes advantage of the viscous state and tensile strength of the extruded clay strand to explore the impact of dynamic extrusion and deformations through travel paths in LDM to manufacture complex porous physical structures. The effects of these parameters are discussed in two case studies: (1) regular and semi-random Spot Deposition surfaces with either open or thickened regions, and (2) porous 3D lattice structures created through the controlled bending of vertical extrusions. The achieved higher geometrical complexity of objects through the algorithmically programmed alternations in the sequence and rate of material deposition allows for a wide range of buildup approaches that expand the production spectrum of sustainable small- and large-scale elements.

Effect of gaps on preform and laminate made by automated dry fiber placement and resin infusion

Automated Dry Fiber Placement (ADFP) provides ease in fiber steering compared to the automated placement of prepregs and a higher material deposition rate than manual hand layup. Vacuum Assisted Resin Infusion (VARI) can be used to infuse the resin into the bed of dry fibers to make the composite. The resin flow rate depends on the permeability of the dry fiber preform, which is dependent on the preform fiber volume fraction. Automated Fiber Placement (AFP) allows the capacity to control the fiber volume fraction in terms of gaps between the tows. So, reducing the fiber volume fraction of preforms by introducing gaps into the preform pattern can increase the permeability. On the other hand, introducing gaps in layup results in a drop in the mechanical properties of the laminate (such as compressive modulus and strength). An optimum gap size may provide a significant gain in permeability with minimum loss in compressive properties. This paper investigates the effect of the gap size in the preform pattern on the preform out-of-plane permeability and compressive properties of the laminate. The out-of-plane permeability of three specimens from preforms, with varying gap sizes (0mm, 0.4mm, and 0.8mm) in all layers were measured. Also, the compressive properties of five coupons made from laminates, with and without gap sizes (0mm, 0.4mm, and 0.8mm) were determined. It was shown that introducing gaps with 0.4 mm size between fiber tapes in the layup can increase the out-of-plane permeability 17 times and reduce the compressive strength and modulus by 6 % and 7.2 %, respectively.

Additive manufacturing of steel components by cold spraying

AbstractDesign of steel structures in the construction industry uses built‐up or rolled steel sections. These are processed as steel elements and connected together at joints. Massive and complex steel nodes such as those in steel frame bridges or truss structures are still manufactured by forging or casting to avoid weld seams in highly stressed areas. Since this is a manual manufacturing process, it results in increased costs and time. Cold spray (CS) technology has recently attracted attention in aerospace and automotive engineering for producing metallic, composite coatings as well as repairing the surface damage of components in service. Additive manufacturing by cold spraying can offer significant advantages with respect to other additive manufacturing methods due to higher material deposition rates (up to 14 kg/h), lower energy consumption, and deposition in solid state. So far cold spraying has not been used for 3D‐printing of typical steel constructions.In the preliminary test campaign, structural steel‐powder was investigated to evaluate their suitability for cold spraying in civil engineering applications. Simple flat specimens were used, and a range of metallographic and mechanical tests were conducted to determine the properties of the deposited coupons, such as the coating quality, layer thickness, the degree of porosity, micro‐hardness, and micro flat tensile test. This paper presents the results of the powder characterisation and the preliminary tests on the printed specimens.

Effects of deposition current density, time and scanning velocity on scanning jet electrodeposition of Ni-Co alloy coating

Jet electrodeposition has superior application prospects in the preparation of nanostructured alloy coatings, which is suitable for high current density deposition and has selective deposition characteristics. The purpose of this work is to clarify the combined effect of multiple factors on the properties of alloy coatings prepared by jet electrodeposition. The L16 made by Taguchi orthogonal array was used in the experiment. The work studied the influence of process parameters such as deposition time (t), current density (i) and scanning velocity (v) on the properties of NiCo alloy coatings prepared on 304 stainless steel, which was set as the substrates. Material deposition rate (MDR), coating microhardness and coating surface roughness (SRa) were selected as the test indicators to characterize the coating properties. Analysis of Variance (ANOVA) was done to analyze the experimental data. The results indicated that current density had the greatest effect on MDR, coating microhardness and coating surface roughness, followed by deposition time and scanning velocity. The optimal parameters combination was selected, listed as follows: deposition time 20 min, current density 70 A·dm−2 and the scanning velocity 10 mm·s−1. The coating microhardness was 532.40 HV, coating SRa was as low as 85 nm, adhesion between coating and substrate was as high as 26.12 N and self-corrosion current density was 5.718 × 10−3 μA·cm−2 under the optimal parameters combination, which showed good performance. This processing method can guide the preparation of NiCo alloy coatings by jet electrodeposition, while the good performance exhibited by the coating can provide a reference for the anti-corrosion and wear-resistant treatment of marine equipment and textile machinery.

UTILIZAÇÃO DA SOLDAGEM POR ARAME TUBULAR NO PROCESSO DE MANUFATURA MECÂNICA

With the ever-increasing competitiveness and the need to deliver products and services faster and with higher quality, the processes involving mechanical manufacturing are constantly developing, so welding has advanced in its technologies and procedures. This work aims to demonstrate that the use of the tubular wire welding process in mechanical manufacturing can be a good alternative for the gain of weld quality and productivity, clarifying the potential of the process, points that should gain more attention, and to other processes, it is hoped to increase the knowledge about welding, especially the tubular wire welding process, which has been gaining prominence in the last decades. By means of the review of available literature, the characteristics of the welding process using tubular wires, technology used, interferences that can occur in the welding, its consequences and the welding behavior by tubular wire in relation to such interferences are studied. In order to do so, the impact of the welding process on tubular wire in the welding quality and weld productivity gain was observed in the mechanical manufacturing, highlighting important points in the welding as a material deposition rate, comparing it with the MIG / MAG process and that its characteristics can bring of effective in front of the critical points of the welding. It was possible to verify that the process of welding by tubular wire brings benefits in several aspects as productive, economic and technical as well as important characteristics of application.

Full-scale investigations of initial deposits formation in a cement plant co-fired with coal and SRF

This work investigates the initial (short-term) deposit formation in a cement calciner co-fired with coal and SRF (Solid Recovered Fuel). The main objective was to evaluate and compare the tendencies of deposit formation (i.e. material deposition rate and composition) at different locations (heights) in the calciner system, during different operation conditions. A steel probe was used to collect initial deposits from four different sampling locations: i) in the kiln riser (two sampling locations), ii) in the mid calciner, and, iii) at the outlet from the bottom stage preheater cyclone (C5). After an exposure time of the probe between 1 and 20 min, the collected deposit samples were weighted and characterized by SEM-EDX, ICP-OES/IC, and XRD. Plant operation data, measured gas temperatures, as well as gas phase composition data (i.e. KCl(g) and SO2(g)), supported the evaluation of deposit formation. Due to high particle flux (up to approx. 61,000 kg/(m2·h) in the riser duct), the average net deposit formation rate was around 500 kg/(m2·h) for 1 min exposure time, decreasing to <100 kg/(m2·h) for exposure times ≥4 min (due to spontaneous shedding and erosion). The deposits contained primarily five crystalline phases (CaO, CaCO3, Ca(OH)2, KCl, and SiO2), which is in general consistence with the composition of the admitted preheated raw meal (C4 meal) at measurement locations, with a slight enrichment in KCl, suggesting some condensation of volatile elements from the high-temperature gas phase on the surface of the somewhat colder deposit particles. Further, the deposit samples obtained in the kiln riser had a higher degree of calcination (higher proportion of CaO as compared to CaCO3) as compared to the admitted C4 meal, suggesting carry-over of dust from the kiln feed pipe, or fast calcination of the riser meal due to high temperature.The collected short-term deposits differ significantly from long-term (mature) deposits, which have previously been collected from the site, in terms of chemical and physical properties. Compared to short-term deposits, which had a content of KCl in the range of approx. 3–5 wt%, the content of KCl in the mature deposits increased substantially from around 2 wt% in samples from the kiln riser area to a level of >20 wt% in the calciner and C5 cyclone area, implying significant accumulation of KCl caused by volatile circulation and condensation from the hot gas on surfaces with locally lower temperatures. The most prevalent crystalline phases in the mature deposits were KCl, CaCO3, and the mineral spurrite (Ca5(SiO4)2CO3). The presence of spurrite implied that SiO2 reacts with CaCO3, or with CaO and gaseous CO2, to form spurrite during long-term deposit build-up and maturation.Overall, the results from this work suggest that the short-term deposit formation in the cement calciner is dominated by impaction. The composition of the short-term deposits is quite similar to the composition of the entrained C4 meal particles; while the build-up of mature deposits is influenced greatly by local temperature gradients and long-term fluctuations. I.e. in zones with locally lower temperatures, such as cold area of calciner walls (< ∼850 °C), heterogeneous condensation and/or thermophoresis of KCl from the high-temperature flue gas is facilitated.

Evaluation of Bronze Electrode in Electrical Discharge Coating Process for Copper Coating.

One of the widely used non-traditional machines for machining of hard materials into complex shapes and different sizes is the electrical discharge machine (EDM). Recently, the EDM has been used for deposition by controlling the input parameters (current and duty cycle). This work was carried out to evaluate the readily available bronze (88% Cu + 12% Sn) electrode for deposition of copper material on titanium alloy. Experiments were conducted according to Taguchi experimental design considering the input parameters of current, Ton, Toff and preheating temperature of substrates. Titanium alloy was further hardened by preheating at temperatures of 100 °C, 300 °C and 500 °C and quenching in brine, castor oil and vegetable oil in order to avoid workpiece erosion. After this treatment, hardness, grain area, grain diameter and number of grains were characterized to compare with pretreated substrates. Then, the treated substrates were taken for copper deposition with the EDM. Output parameters such as material deposition rate (MDR), electrode wear rate (EWR), coating thickness (CT), elemental composition and surface crack density (SCD) were found. Material characterization was carried out using a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) and optical microscopy. Output parameters were optimized with technique for order of preference by similarity to ideal solution (TOPSIS) to find optimum parameters. A sixth experiment with parameter values of Ton of 440 µs, Toff of 200 µs, preheating temperature of 300 °C and quenching medium of castor oil was optimum with MDR of 0.00506 g/m, EWR of 0.00462 g/m, CT of 40.2 µm and SCD 19.4 × 107 µm2.

Influence of deposition rates on the mode I fracture toughness of in-situ consolidated thermoplastic composites

Innovations in recycling, automated and out-of-autoclave processes have renewed significant interests in carbon fibre - polyether ether ketone (CF/PEEK) thermoplastic composites. The crystallinity and, consequently, fracture toughness of semi-crystalline thermoplastics is affected by the cooling rates during processing. Extensive review of published data indicates that in-situ consolidation deposition rates affect PEEK crystallisation. This paper investigates the influence of automated fibre placement (AFP) deposition rates from 76 to 124 mm/s on the crystallinity and mode I fracture toughness of Cytec PEEK polymer matrix with carbon Fibre (AS4/APC2) laminates. The experimental results showed a decrease in crystallinity when the material deposition rate was increased. However, this did not translate into an improvement in fracture toughness. The preliminary study showed an increase in fracture toughness from 76 to 100 mm/s deposition rates. The 124 mm/s samples had the lowest fracture toughness despite having the lowest crystallinity. The crystallinity was not the only driving mechanism in improving the fracture toughness performance and good consolidation is an important factor as well.