Metal Powder Report最新文献

In this work, electromagnetic microwave energy radiations at 2.45 GHz frequency have been utilized to produce 5 mm thick joints of SS304-SS316. Filler powder mixture of fine nickel powder and epoxy blumer 1450XX was taken as interface slurry between the mating faces of the joints. Nano and micro particle sized nickel powder of 70 nm (powder 1), 20 µm (powder 2) and 50 µm (powder 3) were used during three sets of experiments. Activated charcoal powder was utilized as susceptor medium to initiate the microwave heating process. Scanning electron microscopy results showed that the joints were crack free and homogenous. Elemental spectroscopy was carried out to observe and compare the presence of different elemental composition in the joining region with different filler powders.

During machining, adequate cooling and lubrication is much needed to reduce friction, wear, and temperature by efficient heat dissipation resulting in improved surface quality and longer tool life. The various alternative approach developed to provide lubrication and cooling includes minimum quantity lubrication, cryogenic cooling, and machining with the use of solid lubricants. The efficiency of solid lubricant particles greatly depends on the particle size, the wt% of solid lubricant, and base fluid used to prepare a lubricant mixture. Therefore, an attempt has been made in the present investigation, to evaluate the tribological properties of CaF₂ with different grain sizes and weight ratios in a base oil. Results demonstrated the anti-wear and friction ability of CaF₂ as a solid lubricant by improving the tribological properties of sliding surfaces. An increase in friction coefficient is observed with larger grain size (30 and 50 μm) with 10 and 20 wt% of CaF₂ as compared with 10 μm particle size. Results also showed the ability of solid lubricant particles with smaller particle sizes (10 μm) to maintain a thin film of lubrication. As a comparison, CaF₂ mixed with a base oil performed equally well compared to MQL under different loading conditions. The reduction in friction coefficient and wear is observed with solid lubricant application due to its excellent lubricity even at higher load and pressure. The analysis shows the presence of wear on disc surface in the form of visible grooves and wear debris in dry and MQL condition whereas lubricating effects of CaF₂ is dominant.

The use of conventional cutting fluid in metal cutting may increase total production cost and also a threat to the environment and health of the operator. Thus, sustainable and cost-effective measures are to be envisaged to overcome the ill effects of conventional cutting fluids. In this regard, the current study aims to develop an experimental setup for solid lubricant assisted minimum quantity lubrication during machining of Inconel 718. PVD and CVD coated tools are employed for the machining under dry, flood cooling, MQL, and solid lubricant (molybdenum disulfide and graphite) assisted MQL. The influence of these techniques is examined by considering surface roughness, tool wear, chip morphology, and microhardness of the machined surface. Experimental results revealed the effectiveness of molybdenum disulfide assisted MQL in the form of improved tool life and surface finish compared to other machining environments. The results also demonstrated the effectiveness of PVD coated by improving the tool life and surface finish in combination with MQSL compared to selected machining conditions. The presented work may help the metal cutting industries to select the combination of most suitable tool material and lubrication conditions leading towards sustainable machining.

The W-TiC composites with various concentrations of TiC were produced via powder metallurgy. The high energy ball mill was used for the manufacturing of the samples. In this paper, we have selected (Taguchi Analysis) the optimizing parameters such as sintering temperature, and compaction pressure as inputs and corresponding outputs are compressive strength and microstructure. The compressive strength was analyzed by changing the three variances which found that, the compressive strength improved with the addition of TiC. The surface morphology of the sample was verified with SEM examination which confirms the improvement in the strength of material having higher concentration of TiC with higher sintering temperature and compaction pressure.

This paper aims to optimize the wire electric discharge machining (WEDM) parameters using multi response surface methodology. Experiments were performed on Nimonic 80A alloy to improve the response variables, namely material removal rate (MRR) and Kerf width (K_w). SEM analysis was carried out on the different samples obtained using different levels of input input parameters, namely, peak current, gap voltage, duty cycle and wire speed to evaluate the quality of machined surface. The influence of these parameters on MRR and K_w were determined using ANOVA. The analysis results revealed that the peak current is the main factor affecting MRR and K_w. The optimized WEDM parameters obtained using multi response function of RSM technique for machining of Nimonic 80A alloy are peak current (57A), gap voltage (90 V), duty cycle (75 µs), and wire speed (7 mm/min) of wire electrode. The characterization results show that high discharge energy results in deep craters with micro craters at low energy levels on the machined surface of the specimen. The results obtained using the proposed methodology would provide sufficient data for enhancing the machining of Nimonic 80A alloy on WEDM.

Powder based additive manufacturing processes are the most reliable and widely used additive manufacturing processes of present era. Among other parameters, flow of powders within these processes play a critical role in obtaining desirable characteristics of end products. Two most significant parameters which define the flow of powders in additive manufacturing processes are Hausner Ratio and Carr Index. Both Hausner Ratio and Carr Index are theoretically calculated so their numerical values represent the flow character of powders. Since Hausner Ratio and Carr Index are not intrinsic properties of powders therefore an argument exists on their accuracy to determine the powder flow. In this research, an experimental setup is organized to validate the accuracy of Hausner Ratio and Carr Index. The setup consists of a system comprising of three identical powder housing chambers each integrated with a DC servo motor. The speed of motors is controlled by LABVIEW graphical user interface. Three powder lots with similar morphology were used with each having average particle size (d₅₀) equal to 25 µm, 75 µm and 150 µm respectively. The actual flow of powder lots was obtained by using the experimental setup. Results of actual flow were compared with Hausner Ratio and Carr Index of respective powder lots. The effect of particle size distribution on flowability of powders is also discussed.

Several scientists reviewed the influence of the rotation speed and the transverse velocity of devices with friction stir composite processing (FSP) properties. Results proved that significant microstructural changes were affected by altering these parameters. However, the effect of rotation speed and traverse speed of tool has been less explored. Furthermore, no efforts have been made to investigate the consequence of tool velocity ratio so far to wear the aluminum-based metal matrix composites treated with friction stir processed. Therefore, an effort was made in this research to investigate the actuation of the tool speed ratio on the characteristics of aluminum-SiCp composite processed in friction stir processing. Rotational speed and traverse speed of tools selected. In accord to an optimized working range and the corresponding tool velocity ratios were calculated. The FSPed region's morphology, and wear rate were associated with the corresponding tool velocity ratios. It has been identified from this investigation that the device tool velocity of 2.60 resulted in the FSP region with superior resistance to wear compared to other tools velocity ratios.

The ubiquity of artificial intelligence in the manufacturing domain draws inspiration for the present article. The implementation of a neural network technique is still a difficult and time-consuming effort for the industry. Prediction of machining variables is a considerable issue that needs to be explored for preventive maintenance of the machine structure and to optimize the surface quality. This work aims at predicting response parameters of the dry turning process for Inconel 825 alloy using deep-cryogenic treated tungsten-carbide insert through artificial neural network technique. Process parameters considered in this work were cutting speed, feed and depth of cut, whereas, surface-roughness, tool-wear, and material-removal-rate were taken as the three response parameters.14 types of training functions were compared based upon their error indices searching for the training function which best suits this work. Artificial Neural Network (ANN) model was developed by taking Bayesian regularization back propagation based training function. The response values predicted by the ANN were in very close approximation to the actual experimental value with the mean square error of only 0.0011 μm², 39.0882 μm² and 0.0520 cm⁶/min²in the prediction of surface-roughness, tool-wear, and material-removal-rate of dry turning process of Inconel 825 using treated carbide tool.

The aluminum metal matrix composites are becoming futuristic material in automobile and aerospace industries due to their outstanding properties. In this paper, aluminum matrix hybrid composite reinforced with TiB₂ and Gr were fabricated by stir casting route. The weight percentage of TiB₂ and Gr was varied up to 4% and 2% respectively in the matrix material. The mechanical and tribological performance of fabricated composites was studied. The result showed that hardness, ultimate tensile strength and impact strength of fabricated composites enhanced up to 79.59%, 66.76%, and 24.30% respectively as compared to the matrix material. The doping of TiB₂ and Gr in the matrix also enhanced wear performance of composites.