International Journal of Materials and Product Technology (12 papers in press)

Special Issue on: "Materials Processing Technology"
Guest Editor: Dr. Hua-min Zhou, Huazhong University of Science and Technology, China

• Effect of different processes on the microstructure and mechanical properties of the Al-8.5Fe-1.3V-1.7Si/SiCP composite sheet
  by Yi-Qiang He, Zhen-Hua Chen, Na Wang, Ding Chen 
  Abstract: Processes of rolling after extruding and rolling after hot-pressing of multi-layer spray deposited Al-8.5Fe-1.3V-1.7Si/SiCP, and the effect of the two different processes on the microstructure and mechanical properties of the composite were investigated. The microstructure of the composite prepared by different processes was observed by OM, SEM, and TEM. The results showed that more uniform microstructure and more excellent mechanical properties of the composites were obtained by rolling after hot-pressing than rolling after extruding. The excellent mechanical properties can be attributed to avoiding of SiC particles lamination which is familiar to the composite as-extruded by hot-pressing, stable microstructure, and good bonding between SiC particles and the matrix.
  Keywords: hresistant aluminum alloy; composite; spray deposition; hot working
   
• Optimization of extrusion flat die design and die wall temperatures distribution, using Kriging and response surface method
  by nadhir Lebaal, Fabrice Schmidt, Stephan Puissant 
  Abstract: In the present work, a new optimization methodology for the design of coat hanger dies is presented. This method encompasses a numerical simulation code, an objective function and an automatic optimization routine. Two approaches are presented to optimize the velocities distribution across the die exit. In the first approach, we predict the optimal shape of a coat hanger die; in the second approach, in order to keep the same geometry and avoid design and manufacture of a new die, we optimize the temperature of regulation in heterogeneous way. This method involves coupling a three-dimensional finite element simulation software and an optimization strategy. For this optimization the SQP algorithm and the global response surface method with Kriging interpolation are used to minimize the objective function. In the first example, we optimize the geometrical design of the flow distribution channel and in the second example we optimize the die wall temperature distribution.
  Keywords: Polymer extrusion; thermal regulation, Response Surface Method; Optimization; Kriging Interpolation; Finite Element Analysis.
   
• Research on the influences of material properties and forming parameters in T-shaped closed cold ring rolling process
  by Lanyun Li, He Yang, Lianggang Guo, Zhichao Sun 
  Abstract: The influences of the material properties (hardening exponent, Young modulus and yield stress) and the forming parameters (feed amount per driving roll revolution and friction coefficient) on the T-shaped closed cold ring rolling process have been investigated through 3D-FEM. The results show that, the roll force, the roll moment and the diametrical expansion of ring lie on the hardening exponent, the roll force and the roll moment hoik, but the growth rate of ring diameter drops quickly with the increase of hardening exponent; the ring deforms more uniformly with the increase of hardening exponent, yield strength or the feed amount per driving roll revolution or with the decrease of Young modulus; the filling capability of groove improves with the increase of yield strength but worsens with the increase of the other four variables. The achievements may serve as an important guide for selecting rolling equipment and determining the forming parameters of the process. As compared with the experimental data, the 3D-FE model of T-shaped cold ring rolling is valid, ensuring the necessary accuracy of the obtained results.
  Keywords: material property; forming parameter; T-shaped closed cold ring rolling.
   

• Application of the Empirical Mode Decomposition for Determining the Critical Load Buckling of Fiber-reinforced Hybrid Columns
  by Hossein Abolghasem, Farid Taheri, Nader Cheraghi 
  Abstract: Evaluation of the stability of slender structural components has been an ongoing research topic for several decades. Designers use the well-known Euler’s equation to predict the buckling capacity of such structural components. However, when considering the actual response of such components, because of the response being often highly nonlinear, the onset of buckling cannot be distinctly established. As a result, investigators often face difficulty in deciding on the actual buckling capacity of a given component. This becomes even more significant when complex composite structural components are examined. In this paper, a novel approach based on the Empirical Mode Decomposition is introduced for estimating the bucking load of hybrid fiber-reinforced glulaminated columns. The methodology is equally applicable to any column with any initial imperfection and given boundary conditions.
  Keywords: Buckling, stability, empirical mode decomposition, composites, imperfect columns.
   
• FAILURE ANALYSIS AND LIFE PREDICTION OF POLYMERIC ROLLERS FOR INDUSTRIAL APPLICATIONS
  by Andrea Avanzini, Giorgio Donzella, Davide Gallina 
  Abstract: The present study investigates the behaviour of polymeric rollers employed in a cam mechanism of an industrial machine, consisting of two concentrically fitted rings made of polyurethane and short fiber reinforced PEEK. A cyclic mechanical characterization of the materials was at first carried out by strain controlled fatigue tests. The safe range of working conditions of the rollers in terms of rotating speed and contact load was then investigated by rolling contact tests carried out on roller prototypes with a dedicated test rig. These tests allowed obtaining important information about the different damage mechanisms occurring in the component: above a critical working temperature, rollers failure resulted from rings un-fitting due to excessive deformations, while fatigue crack nucleation in the outer ring at the interface with the inner one was observed below this threshold, at high contact load levels. No contact fatigue damage appeared. FEM models of the roller were also developed, based on cyclic material data, in order to analyse the cyclic stress and strain field and to predict the fatigue life, finding a satisfactory agreement with the experimental rolling contact tests results.
  Keywords: Polymers, Thermal softening, rolling contact, fatigue
   
• Large-scale and morphology-controlled synthesis of nano-sized molybdenum disulphide particles by different sulphur sources
  by Xianguo Hu, Peng Jiang 
  Abstract: There have been some chemical routes to synthesize nano-sized MoS2 particles such as hydrothermal method, decomposition of precursors and so on. The decomposition of MoS3 precursors which can be prepared from Na2MoO4 and sulphur sources is a very convenient method to synthesize nanosized MoS2. It was found that the sulphur source had an obvious influence on the morphology and size of MoS3 precursors. The MoS3 precursor prepared from CH3CSNH2 sulphur source contained hollow nano-balls and solid nanoparticles, while that from Na2S sulphur source comprised microsized particles. Heating the obtained MoS3 hollow nano-balls and solid nanoparticles under H2 at 780 oC respectively led to ~150 nm MoS2 hollow-balls and ~40 nm MoS2 solid nanoparticles. However, ~30 nm MoS2 nanoslices were prepared via calcining the prepared MoS3 microsized particles at 780 oC. The all obtained MoS2 samples represented a typical layered structure.
  Keywords: molybdenum disulphide; MoS2; nanoparticles; sulphur source
   
• Identification of rheological models and boundary conditions in metal forming
  by Danuta Szeliga, Maciej Pietrzyk 
  Abstract: Analysis of the method of identification of rheological models and boundary conditions in metal forming is the objective of the work. Various rheological models, from classical ones based on the closed form equations to advanced multi scale models, are investigated. Capabilities and limitations of these models are discussed. Inverse method is applied to identification of rheological parameters and friction coefficient on the basis of various plastometric tests for the carbon manganese steel. Ability of this technique to eliminate effect of inhomogeneity of deformation in the tests is demonstrated. Parameter sensitivity analysis was performed, as well, and the rheological parameters with the strongest influence on FEM simulation results were selected. Finally, accuracy of the inverse analysis is evaluated by calculation of the sensitivity of the flow stress and friction coefficient, determined by this analysis, with respect to the assumptions made in the inverse calculations. Conclusions include good practice guide for selection of rheological model and for identification of parameters of this model.
  Keywords: metal forming; rheological model; boundary conditions; inverse analysis; sensitivity analysis
   
• Artificial Neural Network-based Approach for Detection and Classification of Defects in Polymeric Composites using Machine Vision in SEM study
  by SASWATA BOSE, DEEPAYAN SHOME, CHAPAL DAS 
  Abstract: Miscibility and adhesion of polymeric composites are adversely affected by some micro-structural defects commonly found in polymeric composites. Conventionally, the above-mentioned defects are detected and classified through manual visual analysis of the scanning electron micrographs obtained via scanning electron microscopy (SEM). However, in manual visual inspection of the micrographs, inspection personnel have their own standard of detecting and classifying defects. So, it is quite possible that two different inspection personnel may classify the same defect into two different pre-defined classes of defects. In order to overcome this problem of misclassification, a machine vision-based approach, which utilizes an artificial neural network (ANN) model, is proposed in this study for automated detection and classification of the defects commonly found in polymeric composites. Results obtained reveal that, quite a reasonable level of accuracy in detection and classification of micro-structural defects of polymeric composites is achieved with the proposed approach.
  Keywords: polymeric composites; defect; scanning electron microscopy; machine vision; artificial neural network.
   
• EVALUATION OF THE EFFECTS OF A MOVABLE TOOL IN THE HYDROFORMING PROCESS
  by Gianfranco Palumbo, Luigi Tricarico, Shi-Hong Zhang, Lixin Zhou, Joachim Danckert, Karl Brian Nielsen 
  Abstract: In this paper the production of Stainless Steel hemi-toroidal parts has been investigated using three different processes: the conventional stamping, the standard sheet hydroforming and the hydroforming adopting a movable die (MD) which can have a vertical stroke and whose shape completes the female die cavity. Tests adopting the MD were performed at Aalborg University using a specific experimental equipment; numerical simulations were performed using ABAQUSExplicit and were aimed at investigating the effect of the friction condition of the MD tool on the blank deformation. The friction coefficient was varied on both the whole surface of the MD tool and locally (in the region of the MD corner radius). The role of the MD in the hydroforming process was thus studied by comparing results in terms of thickness and strain distributions on the final part obtained adopting the same geometry of tools but different forming techniques. Simulations put in evidence that a moderate increase of the friction can be successfully used for reducing thinning if the MD is used; in addition, the friction in some regions of the MD tool (MD round corner area) shows to play a key role in forming sound parts.
  Keywords: sheet hydroforming, movable die, hemi-toroidal shape, finite element method
   
• On The Influence of Bond Length on Static Capacity and Fatigue Life of Adhesively Bonded Joints with Composite Adherends Subject To Torsion Loading
  by Ramin Hosseinzadeh, Khaled SHahin, Farid Taheri 
  Abstract: Adhesively bonded joints are being widely used in fiber-reinforced plastic composite (FRP) piping industry for their longevity, ease of installation and reduced stress concentration, among their other positive attributes. Due to the recent popularity of FRP piping, the study of bonded joints, as opposed to the conventional mechanically fastened joints, has gained great importance. The work presented in this paper follows a comprehensive series of study conducted within our research group in characterizing the performance of bonded joints in pipes subjected to torsional loading. The study of bonded joints under static and cyclic torsional loading is extremely scarce in the literature, thus has been the motivation for this work. This study examines the influence of bond (overlap) length on the performance of single lap adhesively bonded joint within FRP tubular adherends under static and cyclic torsional loading conditions. Both experimental and computational methods are used in the investigation to characterize the behavior of the joint. Different failure modes are observed and related to bond length and fabrications related issues. The concept of “effective bond length” is also discussed in detail, with a critical view on its usage in practice.
  Keywords: Adhesively Bonded Joint, Tubular; Adherend; Composite; Cyclic Loading; Torsion; Static Loading; Joint Capacity
   
• Effect of EDM Process Parameters on Surface Quality of Al 6063 SiCp Metal Matrix Composite
  by Akshay Dvivedi, Pradeep Kumar, Inderdeep Singh 
  Abstract: Electric Discharge Machining (EDM) has been successfully used for processing of composites. EDM being a thermal process may results in poor surface quality. Better surface quality may be achieved by proper control of process parameters. This study reports investigation in EDM of Al 6063 SiCp metal matrix composite for the obtained surface quality. White light interferometry is used to evaluate the surface quality in terms of roughness average (Ra) and root mean square average (Rq). Mathematical models are proposed herein for the modeling and analysis of the effects of machining parameters (pulse current, duty factor, gap, lift, sensitivity and flushing pressure) in the EDM process. These models are developed using the response surface methodology. Results have shown that the significant factors affecting the values of the Ra are pulse current, sensitivity and flushing pressure and for the Rq are pulse current, lift, and flushing pressure.
  Keywords: Surface Roughness; Electric Discharge Machining (EDM); Al 6063; Metal Matrix Composite; Response Surface Methodology (RSM)
   
• High pressure jet assisted turning of surface hardened piston rods
  by Davorin Kramar, Peter Krajnik, Janez Kopač 
  Abstract: An experimental study has been performed to investigate the capabilities of dry, conventional and high pressure jet assisted turning of surface hardened piston rods used in high pressure fluid power applications. The capabilities of different hard turning procedures are compared by means of chip breakability, technological windows, cooling lubrication efficiency, tool wear, tool life, and cutting forces. All machining experiments are performed under conventional cutting speeds using coated carbide tools.
  Keywords: Fluid power products, hard turning, high pressure cooling lubrication, machinability, tool wear, chip breakability