Nickel-titanium shape memory alloy (SMA) has been widely used as implant materials due to its good biocompatibility, shape memory property and super-elasticity. However, the severe strain hardening ...is a main challenge due to cutting force and temperature caused by machining. An orthogonal experiment of nickel-titanium SMA with different milling parameters conditions was conducted in this paper. On the one hand, the effect of cutting parameters on work hardening is obtained. It is found that the cutting speed has the most important effect on work hardening. The depth of machining induced layer and the degree of hardening become smaller with the increase of cutting speed when the cutting speed is less than 200 m min−1 and then get larger with further increase of cutting speed. The relative intensity of diffraction peak increases as the cutting speed increase. In addition, all of the depth of machining induced layer, the degree of hardening and the relative intensity of diffraction peak increase when the feed rate increases. On the other hand, it is found that the depth of machining induced layer is closely related with the degree of hardening and phase transition. The higher the content of austenite in the machined surface is, the higher the degree of hardening will be. The depth of the machining induced layer increases with the degree of hardening increasing.
Methyl methacrylate/nitrile butadiene rubber/graphene oxide (MMA/NBR/GO) composite materials were prepared by ball‐milling based on the mechano‐chemical principle. The effects of some key process ...parameters, such as graphene oxide (GO) content, ball‐to‐powder ratio (BPR), and ball‐milling time on textures and structures of MMA/NBR/GO composite materials were studied systematically by Zeta potentials, Raman spectroscopy, Thermogravimetric analysis, Fourier transform infrared spectrometry, and the derivation mechanism was examined. The results indicated composite materials with excellent dispersion stability at GO content of 0.3%, BPR of 3.87, and ball‐milling time of 5 h, the value of sedimentation rate is only 1.0%, the Zeta potential is −41.5 mV, and the mass loss ratio is 40.36%. FT‐IR result shows that the intensity of the characteristic peak all decreases after ball milling, and carboxyl group of GO and hydroxyl group connected to the benzene ring is broken. The graft position is CN and CH2 of NBR, and CH3 of MMA. Under these conditions, the oxygen‐containing functional groups of GO were successfully grafted onto the MMA and NBR.
MMA/NBR/GO composite materials were prepared by ball‐milling based on the mechano‐chemical principle. The effects of some key process parameters, such as graphene oxide (GO) content, ball‐to‐powder ratio (BPR), and ball‐milling time on textures and structures of MMA/NBR/GO composite materials were studied, and the derivation mechanism was examined. The results indicated composite materials with excellent dispersion stability at GO content of 0.3%, BPR of 3.87, and ball‐milling time of 5 h. Under these conditions. The derivation mechanism of MMA/NBR/GO composites is the carboxyl group of GO and hydroxyl group on the benzene ring broke, and GO was then grafted onto NBR and MMA to realize stable dispersion of GO in organic media. For instance, the grafting on NBR occurred at levels of CN and CH2, meaning the presence of CC bond of >CHCN group in NBR and breakage of CC bond in CH2CH2 group. The grafting on MMA took place at CH3, meaning breakage of CO bond in CH3O group of MMA. The structural diagram of the product is provided in Figure 1.
One of the widely used approaches for improving the dissolution of poorly water-soluble drugs is particle size reduction. Ball milling is a mechanical, top-down technique used to reduce particle ...size. The effect of ball number, ball size, and milling speed on the properties of milled Aprepitant is evaluated. A full factorial design was employed to investigate the influence of affecting factors on particle size reduction. The initial suspension was made by suspending the drug in distilled water using excipients followed by milling in a planetary ball mill. Ball size, ball number, and milling speed modulated particle size distribution of Aprepitant. Increasing the number of balls from minimum to maximum for each ball size led to approximately a 28% reduction in mean particle size, a 37% decrease in
, and a 25% decrease in the ratio of volume mean particle diameter to numeric mean particle diameter. On average, using 10 mm balls instead of 30 mm balls reduced mean particle size by 1.689 µm. As a result, ball size, ball number, and milling speed are three effective factors in the process of ball milling. By increasing the ball number and decreasing the ball size, efficient micronization of drug particles takes place and the particle size is more uniform.
This research investigates how different ball milling conditions influence the microstructure and mechanical properties of carbon nanotube/aluminum alloys. The study examines varying rotation speeds, ...specifically 200, 300, and 400 rpm. The results highlight the significant impact of milling conditions on grain size and mechanical properties. Notably, milling at 300 rpm/4 h and at 400 rpm/2 h led to higher tensile strength but lower uniform elongation compared to milling at 200 rpm/6 h. The alloy milled at 300 rpm/4 h displayed a refined microstructure, increased density, and the strongest fiber texture along the (111) direction. The presence of a moderate grain size facilitated ductility, resulting in the highest uniform elongation (∼9.1%) while maintaining high strength (∼515 MPa). This study provides valuable insights into the effects of ball milling on the microstructure and mechanical properties of metals and alloys, contributing to the optimization of milling conditions to achieve desired material characteristics.
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•Preparation of WO3, NiO, Fe2O3 nanoparticles through ultrasonic milling.•The grinding mechanism according to the ball density and ball layer was suggested.•In the ball density ...experiment, the middle density ball showed the highest grinding.•As the layer increased, the contact point increased, so that the grinding was smooth.•Metal oxide nanoparticles exhibited nanoparticle size after hydrogen reduction.
Tungsten-based alloys have been widely applied in various industries due to their excellent mechanical properties. Tungsten-based alloys have a high sintering temperature due to the high melting point of tungsten, so the coarse particles negatively affect the mechanical properties of the alloy. This problem can be solved by increasing the densification by reducing the sintering temperature and time by adding nanoparticles with high surface energy. Herein, we fabricated nanoparticle-sized metal oxides by ultrasonic milling to minimize the influx of impurities to improve the densification of tungsten alloys. The main parameters of the ultrasonic milling experiments were ball density and ball layer. Metal oxides prepared by ultrasonic milling showed an average particle size distribution of less than 200 nm, and metal composite powders prepared through subsequent hydrogen reduction also showed nanoparticle size distributions. We believe that this approach will enable the production of improved sintered tungsten-based alloys.
Temperature progression in a mixer ball mill Schmidt, Robert; Martin Scholze, H.; Stolle, Achim
International journal of industrial chemistry,
06/2016, Letnik:
7, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The influence of the operating frequency, the milling ball and grinding stock filling degree, the material of the milling balls and beakers, the milling ball diameter and the size of the milling ...beakers on the temperature increase inside the milling beakers in a mixer ball mill was investigated. These parameters influence the temperature progression and the equilibrium temperature of the system. The grinding stock filling degree with regard to the void volume in the milling ball package showed huge influence on the heating rate and the equilibrium temperature. In this context, the behavior of the temperature progression changes if the complete void volume is filled with the grinding stock.
High loadings of coarse alumina trihydrate (ATH), commercially used in polymers as a fire-retardant filler, cause uneven dispersion and reduce workability and affect physicomechanical properties. ...Better tensile properties can be achieved by uniform dispersion of nanosize ATH in polymers while maintaining its flame-retardant properties. Consequently, mechanical milling, being a sustainable approach towards the creation of nano-size materials, was carried out to reduce the particle size of coarse ATH in a high-energy planetary ball mill. Investigations were carried out to optimize the milling parameters such as time, rotational speed, milling media size and feed size. During milling, some of the physical properties of ATH change. The energy profile was studied to get the desired product properties. Nano-ATH within the PP matrix reduces the loadings with improvement in tensile and flexural strength. Hence, lightweight PP/nano-ATH composites for suitable use can be developed.
Corrosive environment can influence on hardened steel containing Cr12MoV dies during molding which lead to greatly reduce the service life of the molds. Therefore, it is important to investigate the ...influence of milling parameters on the corrosion resistance of the metal die surface. In this study, single factor cutting tests and electrochemical methods were used to study the effect of processing parameters on the corrosion resistance of Cr12MoV steel die used traditionally in injection molding of plastics. Polarization curve and impedance spectrum of the material was measured in mixed acid solutions under different processing parameters. ZSimpWin software was used to fit the impedance data and to analyze the corrosion resistance of the steel alloy die. The surface morphology after corrosion was observed under a scanning electron microscope (SEM), and elemental analysis was done to characterize the corrosion products. The corrosion resistance of the Cr12MoV die steel had a great correlation with the skewness and kurtosis of the surface morphology parameters. Skewness values closer to zero resulted in smaller kurtosis values and increased corrosion resistance of the machined surface during injection molding. Among different conditions, the change of cutting depth had little effect on the corrosion resistance of the material surface. However, the change in tool radius had a significant impact on the corrosion resistance of the workpiece. The SEM results revealed that the corrosion products were found to significantly accumulate on the surface of the workpiece which was in accordance with the electrochemical results.
Aluminium-based alloys are the most widely used structural material owing to their lightweight, high stiffness with moderate strength, ductility, and toughness. However, these alloys still have ...several issues in engineering applications, such as moderate strength, high temperature, wear-resistant, unstable mechanical characteristics, etc. Intermetallics offer tremendous possibilities for the development of advanced novel material with enhanced mechanical properties for aerospace and automotive applications due to the range of reinforcement materials and flexibility in their primary processing. The current research provides a detailed study of the formation of Cu
9
Al
4
, AlCu, and AlTi
3
intermetallic compounds via mechanical alloying and powder metallurgy route. The microstructural characterisation, compositional analysis, and evolution of different aluminium-based intermetallic compounds with respect to milling time were investigated through field emission scanning electron microscope (FESEM), energy-dispersive spectrometer (EDS), and X-ray diffraction (×RD) analysis. Microstructural analysis revealed that the elemental powder became fine and homogenous as the milling progressed. In addition, the grain structure is homogeneously distributed with a few enlarged and dispersed phases of Y
2
O
3
and TiO
2
in the base alloy. The porosity of the sintered compacts was significantly improved by the addition of 1 wt % each of Y
2
O
3
and TiO
2
dispersoids to 60 h milled base alloy.
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