Grindability Evaluation of Ultrasonic Assisted Grinding of Silicon Nitride Ceramic Using Minimum Quantity Lubrication Based SiO_(2)Nanofluid

Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL system is affirmed to exhibit an excellent machining performance,and it is highly economical.The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL system.Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids.This work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)ceramic.The effect different grinding modes and lubrication systems during the grinding operation was also analyzed.Different concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower oils.The quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface integrity.It was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication systems.Additionally,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%respectively.Finally,regression analysis was used to obtain an optimum parameter combinations.The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.

Improving fatigue properties of normal direction ultrasonic vibration assisted face grinding Inconel 718 by regulating machined surface integrity

Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),and microhardness)after machining processes.Normal-direction ultrasonic vibration-assisted face grinding(ND-UVAFG)has advantages in improving the machinability of Inconel 718,but there is a competitive relationship between higher compressiveσ_(res)and higher surface roughness R_(a)in affecting fatigue strength.The lack of a quantitative relationship between multiple SI indexes and fatigue strength makes theindeterminacy of a regulatory strategy for improving fatigue properties.In this work,a model of fatigue strength(σ_f)_(sur)considering multiple SI indexes was developed.Then,high-cycle fatigue tests were carried out on Inconel 718 samples with different SI characteristics,and the influence of ND-UVAFG process parameters on SI was analyzed.Based on SI indexes data,the(σ_f)_(sur)distribution in the grinding surface layer for ND-UVAFG Inconel 718 samples was determined using the developed model,and then the fatigue crack initiation(FCI)sites were furtherpredicted.The predicted FCI sites corresponded well with the experimental results,therebyverifying this model.A strategy for improving the fatigue life was proposed in this work,which was to transfer the fatigue source from the machined surface to the bulk material by controlling the SI indexes.Finally,a critical condition of SI indexes that FCI sites appeared on the surface or in bulk material was given by fitting the predicted results.According to the critical condition,an SI field where FCI sites appeared in the bulk material could be obtained.In this field,thefatigue life of Inconel 718 samples could be improved by approximately 140%.

Effect of ultrasonic assisted friction stir welding on microstructure and mechanical properties of AZ91-C magnesium alloy

The influence of ultrasonic vibrations on microstructure and mechanical properties of the AZ91-C magnesium alloy after ultrasonic assisted friction stir welding(UaFSW)in comparison with conventional friction stir welding(FSW)was investigated.The FSW was applied at the rotational speed of 1400 r/min and welding speed of 40 mm/min and no defects were observed.Using the same welding parameters,the process was carried out with inducing ultrasonic vibrations to the weld line at the amplitude of 15μm.The microstructure of the specimens was observed with optical and scanning electron microscopy.The results indicate that a very fine microstructure is obtained in UaFSW with respect to that of conventional FSW.Moreover,β-Mg17Al12 coarse dendrites are segregated to very fine and partly spherical particles that homogeneously distribute inα-Mg matrix.This remarkably-modified morphology of microstructure attributed to severe plastic deformation comes from ultrasonic vibration and friction stirring effect.Tensile and hardness tests were performed to evaluate the mechanical properties of the welds.According to the results,the vibration greatly improves the mechanical properties of the conventional FSW joint.The tensile strength and hardness are increased from 195 MPa and HV 79 in conventional FSW to 225 MPa and HV 87 in UaFSW,respectively.

Review: Progress and Trends in Ultrasonic Vibration Assisted Friction Stir Welding

This paper aims to reviewthe state-of-the-art of ultrasonic vibration assisted friction stir welding(UVAFSW) process. Particular attention has been paid on the modes of ultrasonic exertion,experimental results and effects of ultrasonic vibrations on process effectiveness and joint quality. The trends of various aspects with and without ultrasonic vibrations in FSW process are studied and presented. The influence of ultrasonic vibrations on welding loads, temperature history, weld morphology, material flow, weld microstructure and mechanical properties are revisited. Ultrasonic assisted FSW offers numerous advantages over the conventional FSW process. The superimposing of high-frequency vibrations improves various phenomena of the process and the physical,metallurgical,mechanical and tribological properties of the welded joint. The ultrasonic assisted FSW process has a potential to benefit the industry sector. A checklist listing the materials and process parameters used in the documented studies has been presented for quick reference.

Comparison of 2A12 aluminium alloy joint by ultrasonic assisted friction stir welding and friction stir welding

Ultrasonic assisted friction stir welding （UAFSW） is a recent modification of conventional friction stir welding, which adds ultrasonic energy directly into the friction stir welding area by the pin. In this study, 2A12 aluminum alloy was welded by this process and conventional, respectively. The tensile tests, microstructure and fracture surface of FSW joint and UAFSW joint were analyzed. The research results show that the surface forming texture of ultrasonic assisted friction stir welding joint, compared with conventional, is finer and more uniform, showing metallic matte color. The grains are much finer in weld nugget zone, thermo-mechanically affected zone and heat-affected zone; S-phase particles size is much smaller and distribution is more homogeneous in the matrix. The tensile strength of UAFSW joint is 94. 13% of base metal, and the elongation is 11.77%. The tensile strength of FSW joint is 83.15% of base metal, and the elongation is 8.81%. The tests results reveal that ultrasonic vibration can improve the tensile strength and the elongation of welded joints.

Comprehensive modeling approach of axial ultrasonic vibration grinding force

The theoretical model of axial ultrasonic vibration grinding force is built on the basis of a mathematical model of cutting deforming force deduced from the assumptions of thickness of the undeformed debris under Rayleigh distribution and a mathematical model of friction based on the theoretical analysis of relative sliding velocity of abrasive and workpiece. Then, the coefficients of the ultrasonic vibration grinding force model are calculated through analysis of nonlinear regression of the theoretical model by using MATLAB, and the law of influence of grinding depth, workpiece speed, frequency and amplitude of the mill on the grinding force is summarized after applying the model to analyze the ultrasonic grinding force. The result of the above-mentioned law shows that the grinding force decreases as frequency and amplitude increase, while increases as grinding depth and workpiece speed increase; the maximum relative error of prediction and experimental values of the normal grinding force is 11.47% and its average relative error is 5.41%; the maximum relative error of the tangential grinding force is 10.14% and its average relative error is 4.29%. The result of employing regression equation to predict ultrasonic grinding force approximates to the experimental data, therefore the accuracy and reliability of the model is verified.

Effect of ultrasonic assisted sintering on mechanical properties and degradation behaviour of Mg15Nb3Zn1Ca biomaterial

The present work investigates the effect of ultrasonic power(%)and the time of ultrasonic vibration on the sintered density and ultimate compressive strength(UCS)of Mg15Nb3Zn1Ca fabricated using ultrasonic assisted conventional sintering(UACS).The customized UACS setup was designed and manufactured to conduct the experimentations.A customized ultrasonic stepped horn assembly was used for providing vibrations to the sample during sintering.Further,to evaluate the efficacy of ultrasonic vibration parameters,the developed setup was used to sinter Mg15Nb3Zn1Ca composite material.The study unveiled an increased sintered density and UCS of the fabricated sample by the increase in ultrasonic power(%).Moreover,a decrease in sintered density and UCS was observed with an increase in the time of ultrasonic vibration beyond a certain limit.Samples sintered with the assistance of ultrasonic vibration at 100%ultrasonic power,and 20 min of ultrasonic vibration resulted in a sintered density of 1.928±0.062 g·cm^(-3)and UCS of 234.9±12.3 MPa.The obtained mechanical properties of the fabricated sample were comparable to the properties of cortical bone.The surface morphology and elemental compositions of samples fabricated using UACS declared a fair dispersion of reinforcement in the matrix containing merely the source elements.The results of corrosion test have showed that the assistance of ultrasonic vibration suppressed the degradation behaviour of the sintered sample after performing electrochemical study of samples using 3-electorde cell voltammetry.Mg15Nb3Zn1Ca fabricated using UACS showed a 50.18%and 9.08%of reduction in corrosion rate over conventionally sintered pure Mg and Mg15Nb3Zn1Ca respectively.In addition,electrochemical impedance spectroscopy(EIS)results indicated an enhanced corrosion resistance of the Mg15Nb3Zn1Ca composite material when fabricated at 100%of ultrasonic power with 20 min of vibration time.Apart from that,electrochemical equivalent circuits also resulted in good fitting of the experimental data obtained from EIS.

Ultrasonically Assisted Cutting of Histological Sections for Reducing the Environmental and Financial Impact of Microtomy

Modern-day microtomy requires high precision equipment to thinly section biological tissues.The sectioned tissue must be of good quality not showing cutting tracks or so-called artefacts.The quality of these sections is dependent on the blade wear,which is related to the hardness of the tissue sample,cutting angle and cutting speed.A test rig has been designed and manufactured to allow these parameters to be controlled.This has allowed for the blade wear to be analysed and quantified,and this has been completed for both ultrasonically assisted and conventional cutting.The obtained results showed a 25.2%decrease in average blade roughness after 38 cuts when using the ultrasonically assisted cutting regime.The data also showed no adverse effect on the quality of the slides produced when using this cutting methodology.Finally,the cutting force measured for both cutting regimes showed that ultrasonically assisted cutting required less force compared to conventional cutting.With the reduction of surface roughness and force,it is possible to state that ultrasonically assisted cutting reduces the wear of the blade,thereby increasing the life of the blades.An increase of just 10%in blade life would yield a cost saving of approximately 25%thereby reducing the environmental and financial impact of microtomy.

Separate critical condition for ultrasonic vibration assisted grinding

Separate characteristic of the tangential ultrasonic vibration assisted grinding (TUAG) machining is analyzed based on TUAG process, and a critical speed formula is given to correctly set the machining parameters to insure the separate characteristics of TUAG process. The critical speed is not only related to the ultrasonic vibration amplitude and frequency, but also to the grinding wheel velocity and the cutting point space, and the grinding force can be decreased during the TUAG process with separability. Grinding force experiments are conducted, and the experimental results are in good agreement with the theoretical results.

Ultrasonic wave extraction and simultaneous analysis of polycyclic aromatic hydrocarbons (PAHs) and phthalic esters in soil

A method is developed for detection of polycyclic aromatic hydrocarbons(PAHs) and Phthalic Acid Esters(PAEs) in soil samples. Ultrasonic Wave Extraction under airtight circumstances is adopted to extract the analytes in soil samples with n-hexane–acetone(V:V=1:1) as extraction solvent. This method has several advantages, including high extraction efficiency, short time, convenience and simplicity. It can be used to detect polycyclic aromatic hydrocarbons(PAHs) and Phthalic Acid Esters(PAEs) in soil.

GC-MS Analysis of Essential oil and n-Hexane Extract from Moso Bamboo

[Objective] This study aimed to analyze the chemical composition and yield of essential oil and n-hexane extract from moso bamboo to find active compounds with potential value. [Method] Essential oil and n-hexane extract were respectively extracted from moso bamboo of four different ages by using hydrodistillation and ultrasonic-assisted extraction with n-hexane, and analyzed with gas chromatography/mass spectrometry （GC/MS）. [Result] The results show that cedrol （46.39%） is the first principal volatile component in essential oil of the middle stem of 7-year old moso bamboo; dibutyl phthalate （59.46%） is the first principal volatile component in n-hexane extract of the middle stem of 3-year old moso bamboo; yield of n-hexane extract is higher than that of essential oil from moso bamboo. [Conclusion] Cedrol is an active compound with potential value.

Study of joining mechanism of ABS polymer and steel/aluminum by resistance spot welding

The joining of metal and polymer is an increasingly important method to get lightweight components in the development of manufacturing industry- nowadays. In this artiele, metal and polymer lap joint was achieved by means of resistance spot welding （RSW） and ultrasonic assistance welding （UAW）. The joining mechanism of lap joint was analyzed by OM, TEM on microstructure at the interface of lap joints and XPS and IR spectra was discussed based on the following different ones： mechanical-interlocking, diffusion bond and coordination bond. The results showed that it was the combined action that played an important role in the effective joining work. Besides, ultrasonic assistance was used in the study to aid welding process based on its high-frequency ultrasonic vibration, which made joints shaping better and improved tensile strength visibly contrast to joints with the same lower heat input parameters.

Experimental Investigation and Numerical Simulation on Interfacial Carbon Diffusion of Diamond Tool and Ferrous Metals

We numerically simulated and experimentally studied the interfacialcarbon diffusion between diamond tooland workpiece materials.A diffusion modelwith respect to carbon atoms of diamond toolpenetrating into chips and machined surface was established.The numericalsimulation results of the diffusion process revealthat the distribution laws of carbon atoms concentration have a close relationship with the diffusion distance,the diffusion time,and the originalcarbon concentration of the work material.In addition,diamond face cutting tests of die steels with different carbon content are conducted at different depth of cuts and feed rates to verify the previous simulation results.The micro-morphology of the chips is detected by scanning electron microscopy.Energy dispersive X-ray analysis was proposed to investigate the change in carbon content of the chips surface.The experimentalresults of this work are of benefit to a better understanding on the diffusion wear mechanism in single crystaldiamond cutting of ferrous metals.Moreover,the experimentalresults show that the diffusion wear of diamond could be reduced markedly by applying ultrasonic vibration to the cutting toolcompared with conventionalturning.

Chinese Herbs as an Example for a New Class of Feed Ingredients in Aquatic Animal Diets

Chinese herbal flavonoids play a role in improving the health of aquatic animals and optimizing the quality of aquatic products.The efficient extraction of flavonoids is beneficial to deepening the application of flavonoids in aquatic products.To explore the optimal way of flavonoid extraction has become a hot research topic.In this study,based on temperature,ultrasonic power and extraction time,the best ways to extract flavonoids from four Chinese herbal medicines,purslane,Verbena,Fructus Amomi and Alpinia oxyphylla,were explored.Through single-factor and multi-factor optimization extraction,the most appropriate conditions for flavonoid extraction were obtained.The results showed that the best way of ultrasonic assisted extraction of flavonoids was purslane at 40℃,300 W(400 W),Verbena at 70℃,400W,Fructus Amomi at 50℃,200 W,and A.oxyphylla at 40℃,400W,and 40 min.The results of orthogonal design showed that purslane could get 13.20 mg/g at 40℃,400 W and 50 min,Verbena could get 10.23 mg/g at 60℃,300 W and 30 min,Fructus Amomi could get 8.18 mg/g at 50℃,300 W and 60 min,and A.oxyphylla could get 7.31 mg/g at 30℃,300 W and 50 min.

Ultrasound Promoted Synthesis and Antimicrobial Evaluation of Novel Seven and Eight-Membered 1,3-Disubstituted Cyclic Amidinium Salts

Series of 1,3-dibenzyl-1H-4,5,6,7-tetrahydro-1,3-diazepinium and 1,4,5,6,7,8-hexahydro-1,3-diazocinium salts derivatives were efficiently synthesized in excellent yields by dehydrogenation of the corresponding N,N'-dibenzyl aminals employing N-bromosuccinimide (NBS) as dehydrogenating agent under ultrasound irradiation. The present methodology has proven to be simple, efficient and environmentally benign. All novel compounds were identified and characterized by 1H and 13C NMR spectra. The synthesized compounds were screened for their antimicrobial activities.

Aromatization of virgin olive oil by seeds of Pimpinella anisum using three different methods:Physico-chemical change and thermal stability of flavored oils

Knowing that flavored products would increase the use of olive oil by non-traditional consumers and enhance the added value of this valuable agricultural product,the virgin olive oil(VOO)was flavored with the seeds of Pimpinella anisum(Green anise)using three different methods:classic maceration,ultrasonic assisted maceration and direct addition of the essential oil(EO).These methodswere compared under two main criteria:time and level of aromatization.The physico-chemical parameters and the thermal stability of flavored oils prepared by the three methods were determined by AOAC titration method and GC–MS analysis so as to compare the aromatization effect of the three methods.The trans-anethole is the major component of the EO of anise seeds as well as the indicator of the level of aromatization.GC/MS analysis results of the flavored oils showed that the diffusion of trans-anethole in the flavored oil by direct addition of EO was very important(36.3%of the total volatile fraction of the flavored oil)in comparison to the oil flavored by ultrasonic assisted maceration or classic maceration(respectively 26.59%and 23.85%).These different aromatization methods ensure an improvement in the quality of VOO with an enrichment in polyphenols estimated at 35%in the case of ultrasonic flavored oil,an increase in the content of carotenoids and chlorophylls(67%and 21%respectively)in the event of aromatization by classic maceration,and a decrease in specific absorbency at 232 nmestimated at 29%during aromatization by addition of EO as well as a decrease in the peroxide value estimated at 26%in oil flavored by classic maceration unlike in oil flavored by ultrasoundwhich has seen an increase of around 20%.The aromatization was able to maintain the stability of the oils and its qualification as VOO with a gain in induction time in the case of treatment at 60℃ estimated at 29 and 27.5 d respectively in oils flavored by addition of EO and by conventional maceration,an improvement resistance to degradation concerning K_(232) and K_(270) of all flavored oils which varied from 15 to 40 d in the case of treatment at 60℃ and 3 h resistance to degradation of oils treated at 130℃ for K_(232).Polyphenols,chlorophyll pigments and carotenoids play an important role in oxidative stability due to their antioxidant nature and their degradation during heating is very complex.All of these physico-chemical changes have increased the thermal stability of flavored oils with better resistance to oxidation of flavored oil by classic maceration in compared to oil flavored by adding EO and the oil flavored by using ultrasound.

Ultrasonic vibration assisted tungsten inert gas welding of dissimilar magnesium alloys

The effects of ultrasonic vibration assisted（UVA） treatment on the microstructures and mechanical properties of MB3/AZ31 dissimilar magnesium（Mg） alloy joints were studied by microstructural characterization, micro-hardness testing and tensile testing. Results indicate that the welding pores are eliminated and coarse a-Mg grains of fusion zone are refined to 26 μm, owing to the acoustic streaming effect and cavitation effect induced by the UVA treatment with an optimal ultrasonic power of 1.0 kW.In addition, Mg;Al;precipitation phases are fine and uniformly distributed in the whole fusion zone of weldment. Micro-hardness of fusion zone of the Mg alloy joints increases to 53.5 HV after UVA process,and the maximum tensile strength with optimized UVA treatment increases to 263 MPa, which leads to fracture occurrence in the Mg alloy base plate. Eventually, it is experimentally demonstrated that robust MB3/AZ31 Mg alloy joints can be obtained by UVA process.

Effect of ultrasonic vibration on finished quality in ultrasonic vibration assisted micromilling of Inconel718

Inconel718 was machined with the traditional micromilling(TMM)and ultrasonic vibration assisted micromilling(UVAMM)with the different technology parameters,whose surface quality and burrs formation were studied.The results show that TMM often forms pits,bumps and gullies in the size effect range.UVAMM effectively improves the surface quality compared with TMM.The surface defects are significantly reduced with the increase of feed per tooth(fz).When fz exceeds 4 lm,the effect of ultrasonic vibration on the surface quality is no longer obvious.The minimum burr size on the down milling side and the up milling side are 50.23 lm and 36.57 lm,respectively.The feasibility of vibration cutting in improving surface quality and suppressing burr size was verified.UVAMM effectively suppresses the formation of built-up edge,which can significantly improve the micromilling process.The cutting force is obtained through simulation and experiment.They are agreement in the change trend.The finite element simulation can be used to predict the cutting force.Compared with TMM,feeding force(Fx),radial force(Fy)and axial force(Fz)of UVAMM decrease by 7.6%,11.5%and 1.3%,respectively.

Influence of longitudinal-torsional ultrasonic-assisted vibration on micro-hole drilling Ti-6Al-4V

As Ti-6 Al-4 V is a typical hard to machine material,especially in micro drilling aviation parts,chip breaking difficulty is of increasing interest to explore its further development.In this study,Longitudinal-Torsional Ultrasonic Assisted Drilling(LTUAD)was employed to machine Ti-6 Al-4 V,and its feasibility was evaluated by comparing with Conventional Drilling(CD).By combining periodical characteristics and vibration models(the separated or the unseparated ultrasonic elliptical vibration),the influence of ultrasonic frequency on the intersection characteristics of trajectories were analyzed.And the intersection characteristics were divided into four categories:even periodicity,odd periodicity,non-odd and even periodicity and composite periodicity,indicating different capability for chip breaking.By applying the longitudinal-torsional compound vibration horn,the micro-hole drilling experiment was carried out on machining center.The chip morphology,the thrust force,and the burr height were discussed.Experimental results showed that the morphology of chips presented as smaller and more fragmentary ones in LTUAD compared with continuous helical conical ones and fold-shaped ones in CD.Compared with CD,the average values of the thrust force in LTUAD reduced by 1.98%to 24.9%.According to the burr around the hole exit in both LTUAD and CD,the height of the latter was greatly affected by the drilling parameters.And the burr around the exit of the hole were distributed rather evenly with smaller extension in LTUAD.Consequently,the LTUAD employed in micro-hole drilling was effective.

Research on ultrasonic-assisted drilling in micro-hole machining of the DD6 superalloy

The DD6 nickel-based superalloy exhibits remarkably high temperature properties;therefore,it is employed as a crucial structural material in the aviation industry.Nevertheless,this material is difficult to process.Ultrasonic-assisted drilling(UAD)combines the characteristics of vibration processing technology and conventional drilling technology,significantly improving the machinability of difficult-to-machine materials.Thus,UAD experiments were performed on micro-hole machining of DD6 superalloy in this study.The effects of amplitude,frequency,spindle speed,and feed rate on thrust force,machining quality,and drill bit wear were studied;thereafter,a comparison was drawn between these effects and those of conventional drilling(CD).The experimental results reveal that the thrust force decreases with an increase in spindle speed or a decrease in feed rate for both UAD and CD.UAD can significantly reduce the thrust force.With the same processing parameters,the greater the amplitude,the greater the reduction of the thrust force.The surface roughness of the hole wall produced by UAD is lower than that of CD.Compared with CD,UAD reduces the burr height,improves machining accuracy,and reduces drill bit wear.