This paper aims to explore the influence mechanism of different Al contents on the mechanism of CoCrFeNiAlX high entropy alloy micro-milling by studying CoCrFeNi (Al0), CoCrFeNiAl0.6 (Al0.6) and ...CoCrFeNiAl (Al1). The law of changes in the temperature field, cutting force, residual stress, and surface roughness of Al0, Al0.6 and Al1 is investigated by the simulation method. The research results showed that the chips produced during the milling of three workpieces with different Al contents are different in the milling process. In particular, those produced by Al0 are shaped like long flakes and easy to adhere to the milling part, thus leading to short-duration chip accumulation. This is also the reason why the milling temperature of Al0 is obviously higher than that of Al0.6. The milling temperature of each workpiece gradually increases with the increase in milling speed, reaching the maximum when the milling speed reaches 450 mm/s. At the same milling speed, the milling temperature of each workpiece is sequenced as follows: Al1>Al0>Al0.6. Also, the milling temperature of the three types of workpieces shows an upward trend within a complete milling cycle, with the maximum milling temperature being far lower than that of traditional milling. With the increase in milling speed, the changes in the cutting forces of Y and Z directions are virtually the same for the three types of workpieces with different Al contents. However, the influence of milling speed on X-direction cutting force is relatively complex. The X-direction cutting force of Al1 and Al0 changes little, almost forming a horizontal line, while that of Al0.6 tends to increase first and then decrease. With the increase in milling speed, all the three-way cutting forces of three types of workpieces increase. With the increase in the feed rate, for each workpiece with three different Al contents, the X-direction cutting force first rises and then falls; the Z-direction cutting force tends to decrease gradually and the Y-direction cutting force almost forms a horizontal line. Also, the cutting force of Al0.6 is the smallest among the three under the same parameter and its peak value in the X direction is 68% of that of Al1 and 93% of that of Al0. With the increase in milling speed and milling depth, the changes of the residual stress for the workpieces with three different Al contents tend to be “spoon” shaped and the peak value of the residual stress for each workpiece is sequenced as follows: Al1>Al0.6>Al0. Among them, the peak value of residual stress for Al0.6 is 57% of that of Al0. The machined surface roughness of Al0.6 is the smallest after the whole micro-milling process is completed for the three types of workpieces with different Al contents.
•The micromachining mechanism of CoCrFeNiAlX high entropy alloys with different elemental contents is revealed.•The residual stresses of micromachining CoCrFeNiAlX high entropy alloys with different elemental contents are investigated.•The law of the influence of Al element on the cutting force and temperature of CoCrFeNiAlX high entropy alloys is studied.
As (III) is widely distributed in groundwater which is relatively harder to be removed comparing to As (V). Co-grinding Ca(OH)2 with Al(OH)3 was conducted to manufacture katoite (Ca3Al2(OH)12) for ...the complete removal of As(III) (concentration below drinking water standard of WHO (<10 ppb)) during one-step agitation operation. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS) were applied for the illustration of adsorption mechanism. Katoite could intercalate As(III) into the layered space forming arsenite pillared Ca-Al layered double hydroxide (LDH). The coexisting anions such as Cl−, SO42−, and NO3− had minor effects on As (III) removal performance using katoite. Techno-economic analysis demonstrated the feasibility of large-scale katoite production and its practical application for As(III) polluted groundwater purification, especially in the undeveloped areas where groundwater was used as irrigation and drinking water.
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•Co-milling Ca(OH)2 with Al(OH)3 to produce katoite ((Ca3Al2(OH)12).•As(III) (concentration <50 ppm) removal by katoite forming arsenite pillared Ca-Al LDH.•As(III) (concentration >50 ppm) precipitation by katoite forming calcium arsenite.•Excellent adsorption selectivity of katoite toward As(III) over coexisting anions.
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•Autogenous stirred media milling of silicon.•Size and shape analysis of new and used autogenous grinding media.•Wear rate of new and used autogenous grinding media.•Milling ...efficiency of autogenous grinding media and comparison to stirred media milling with ceramic spheres.
This study investigates the wear mechanisms and milling efficiency of silicon as grinding media for autogenous stirred media milling. Fresh autogenous grinding media (aGM) showed an exponentially decreasing wear rate first, while becoming constant at longer grinding times. The wear rate of used aGM was constant throughout the whole milling experiment. Shape and size analysis revealed that chipping and abrasion mechanisms dominate the wear behavior. These mechanisms led to spheroidization of the aGM. The grinding media concentration was introduced as measure for the energy transfer from the stirrer to the product particles. This concept was used for weighting the specific energy consumption. Nanoparticles of around 150 nm were obtained with similar weighted specific energy consumptions, while used aGM performed most efficiently due to their spheroidized shape. Finally, spheroidized aGM still consumed more weighted specific energy than conventional grinding media. However, a direct comparison was difficult due to the different material properties of the grinding media.
Micro milling is a widely used manufacturing method. The main purpose of this study is to analyze the cutting forces in corrosion-resistant, heat-resistant steel 14Kh17N2. Studies of the full ...factorial experiment on the processing of steel 14Kh17N2 are carried out using a micro end mill with AlTiN coating. New mathematical models of cutting force and axial force have been developed that are adequately able to predict and optimize the forces acting on the cutting tool. Graphs have been obtained for calculating the minimum required feed per tooth and depth of cut, at which maximum cutting forces and axial forces are provided, which makes it possible to increase the durability of the cutting tool during microfilming. The obtained mathematical models describe the obtained experimental data with 90% or more accuracy.
Full-discretization methods beyond the third order is not yet explored except for this work in which the fourth and fifth order methods are presented. It is seen in earlier works that accuracy of ...milling stability analysis using the full-discretization method rises from the first order method to the second order method and continues to rise to the third order method. It is seen in this work that the rise in accuracy of the full-discretization method with order continues to the proposed fourth order method where it (accuracy) peaks before a decline to the proposed fifth order method.
•Simplified systematic derivation of full-discretization methods of hyper-third order is presented.•Accuracy peaked at 4th order among the full-discretization methods of 1st to 5th order.•The proposed methods are applicable to stability analysis of milling of higher degree of freedom.
Edge‐selectively halogenated graphene nanoplatelets (XGnPs, X = Cl, Br, or I) are prepared by a simple mechanochemical ball‐milling method, which allows low‐cost and scalable production of XGnPs as ...highly stable anode materials for lithium‐ion batteries.
An effective thread milling force prediction model considering instantaneous cutting thickness is presented based on the cylindrical thread milling simplified to the side milling process. Firstly, ...based on the thread milling process simplified to side milling, an effective calculation model of instantaneous cutting thickness and a milling force model of single-layer cutter teeth are established considering the specific geometric profile of the cutting edge, chip groove angle, and tooth profile angle of the threaded milling cutter. Then, according to the time-domain difference of each layer of cutter teeth, a simplified thread milling force prediction model corresponding to the number of layers can be obtained. Finally, comparing the predicted values of the proposed model with the experimental results of cylindrical thread milling forces, the results show that the average prediction accuracy of
F
x
,
F
y
, and
F
z
are 90.75%, 83.56%, and 78.79%, respectively. The established simplified cylindrical thread milling force prediction model is accurate and reliable.
With a series of merits, Prussian blue analogs (PBAs) have been considered as superior cathode materials for sodium‐ion batteries (SIBs). Their commercialization, however, still suffers from inferior ...stability, considerable Fe(CN)6 defects and interstitial water in the framework, which are related to the rapid crystal growth. Herein, a “water‐in‐salt” nanoreactor is proposed to synthesize highly crystallized PBAs with decreased defects and water, which show both superior specific capacity and rate capability in SIBs. The air‐stability, all‐climate, and full‐cell properties of our PBA have also been evaluated, and it exhibits enhanced electrochemical performance and higher volume yield than its counterpart synthesized via the water‐based co‐precipitation method. Furthermore, their highly reversible sodium‐ion storage behavior has been measured and identified via multiple in situ techniques. This work could pave the way for the PBA‐based SIBs in grid‐scale energy‐storage systems.
A facile, cost‐efficient, and general programmable ball‐milling synthesis process without any additives was designed to prepare highly crystalline MnHCF‐S‐170. The constructed sodium‐ion batteries (SIBs) based on the above MnHCF‐S‐170 can adapt to the complex and fickle working environment, and demonstrate possible practical applications in large‐scale energy‐storage systems.
Exploring advanced green processing technology is the way to achieve efficient precision manufacturing of difficult-to-machine materials and carbon-neutral development. Thus, the design and ...manufacture of a large-amplitude longitudinal ultrasonic vibration-assisted milling (LALUVAM) toolholder is conducted in this work. For validation of the developed toolholder a TC4 titanium alloy milling experiment is carried out. Multifaceted analysis are presented in terms of milling force, surface roughness, and residual stress. The results indicate that the LALUVAM toolholder exhibits excellent performance in milling TC4 materials. What’s more, the disordered tool feed trajectory is eliminated when using the LALUVAM toolholder in milling TC4. Moreover, resultant forces
F
is reduced 36.61%. The minimum surface roughness and a smaller range of compressive residual stress can be obtained under LALUVAM condition. Meanwhile, a scaled texture can be generated on the surface of TC4 by using harmonic movement of end mill. In the future, LALUVAM toolholder will be able to meet the 10 μm to 20 μm ultrasonic machining and provide better results in terms of reduced milling forces and surface roughness.
An experimental investigation and comparative analysis of the residual stress state between micro- and meso-milling processes with a ball-end mill on the Ti–6Al–4V titanium alloy were carried out. A ...methodology to study the characteristic kinematics of a five‑axis machining process in a three-axis vertical machining centre was proposed. The study considers the chip formation process according to the lead and tilt angles of the tool axis concerning the normal vector of the surface. When using the up‑milling cutting strategy, the defect of smeared/adhered material to the surface occurs in both the micro- and meso-milling levels, associated with the build-up edge and build-up layer phenomenon. The residual stress tensor of the surface was obtained through the X-ray diffraction technique. The down-milling cutting strategy produced the best surface finish and higher compressive residual stresses. The experiments showed higher compressive residual stresses in the feed direction than in the cross-feed direction. The micro-milling process produced higher compressive residual stresses than those observed in the meso-milling process.
