Frictional properties of AZ80 and ZE10 magnesium alloys under dry and lubricated contact conditions

The frictional properties of two types of magnesium alloys, i.e. AZ80 and ZE10 were investigated. A purpose-developed sheet metal forming simulator was used to conduct the experiments under constant plastic deformation. Both lubricated and dry sliding contact conditions were simulated and the effect of key process parameters such as contact pressure and sliding velocity on the frictional properties of these alloys were investigated. Due to the different sliding velocities, the contact pressure rose during each experiment which enables the measurement of the coefficient of friction for a wide range of contact pressures. The results showed an increase in the friction coefficients of both alloys with increasing contact pressure. Furthermore, a decrease of the friction coefficient was observed for higher sliding velocities. (C) 2014 The Authors. Published by Elsevier Ltd.Ramezani, M.; Neitzert, T.; Pasang, T.; Sellés Cantó, MÁ. (2014). Frictional properties of AZ80 and ZE10 magnesium alloys under dry and lubricated contact conditions. Elsevier. doi:10.1016/j.proeng.2014.10.242

Tribology Properties on 5W-30 Synthetic Oil with Surfactant and Nanomaterial Oxide Addition

This study analyzes the tribological properties of 5W-30 synthetic oil with the addition of surfactants and oxide nanomaterials. This research used SAE 5W-30 lubricant base material with the addition of Aluminum Oxide (Al2O3), Titanium Dioxide (TiO2), and Hybrid Aluminum Oxide (Al2O3) - Titanium Dioxide (TiO2) nanomaterials. The nano lubricants were synthesized using a two-step method by adding nanomaterials by 0.05% volume fraction, followed by 50 ml of 5W-30 synthetic oil and polyvinylpyrrolidone (PVP) surfactant by 0.1%. Then, it was stirred using a magnetic stirrer for 20 minutes, followed by an ultrasonic homogenizer process for 30 minutes. Further, the nanolubricant was tested to identify its thermophysical properties, including density, dynamic viscosity, and sedimentation. It also underwent tribological testing, including wear, coefficient of friction, and surface roughness. Further, the nanomaterial was characterized using SEM, XRD, and FTIR. The morphological analysis using SEM suggested an irregular shape of the Al2O3 nanomaterial surface, while TiO2 has a spherical shape. Besides, phase identification with XRD testing showed corundum and anatase phases. Functional group analysis through the FTIR showedthe presence of Ti-O and Al-O. The highest density and viscosity results without surfactants were obtained in hybrid nanolubricant 779 kg/mm3 and 0.0579 Pa.s, while the use of surfactants resulted in 788.89 kg/mm3 of density and 0.0695 Pa.sviscosity. Tribological gray cast iron FC25 results in the best COF value observed in SAE 5W-30 + PVP-TiO2 lubrication (0.093). The lowest wear mass without surfactant was obtained in the Al2O3-TiO2 nanolubricant hybrid (0.02 grams), the lowest surface roughness in a mixture of PVP and TiO2 surfactants was 0.743 μm. Meanwhile, the surface morphology of gray cast iron FC25 with hybrid nanolubricant SAE 5W-30 (Al2O3-TiO2) and Nanolubricant SAE 5W-30+ (PVP-TiO2) produced the smoothest surface

Effects of Increasing Feed Rate on Tool Deterioration and Cutting Force during End Milling of 718Plus Superalloy Using Cemented Tungsten Carbide Tool

Understanding how feed rate (ft) affects tool deterioration during milling of Ni-based superalloys is practically important, but this understanding is currently insufficient. In the present study using a 718Plus Ni-based alloy and cemented tungsten carbide tool inserts, milling experiments were conducted with ft = 0.10 mm/tooth under either dry or wet (with coolant) conditions. The results are compared to those based on using ft = 0.05 mm/tooth from previous studies. The milling force (F) was monitored, the cutting tool edge was examined and the flank wear (VBmax) was measured. As would be expected, an increase in ft increased F. It was found that F correlated well with VBmax for the high ft (0.1 mm/tooth) experiments, as opposed to the previously observed poor F-VBmax relationship for the lower ft (0.05 mm/tooth) value. This is explained, supported by detailed failure analysis of the cutting tool edges, by the deterioration mode to be dominantly edge chipping with a low occurrence of fracturing along the flank face when the high ft was used. This dominancy of the deterioration mode means that the tool edge and workpiece contact was consistent and thus resulted in a clear F-VBmax relationship. A clear F-VBmax relationship should then mean monitoring VBmax through monitoring F is possible

A case study on effect of feed rate on machinability of austempered ductile iron

Austempered Ductile Iron (ADI) is a type of nodular, ductile cast iron subjected to heat treatments - austenitising and austempering. Whilst machining is conducted prior to heat treatment and offers no significant difficulty, machining post heat treatment is demanding and often avoided. Phase transformation of retained austenite to martensite leading to poor machinability characteristics is a common problem experienced during machining. This case study explains the effect of feed rate on machinability of ADI using cutting force analysis and tool failure analysis. The experimental design consists of conducting drilling trials on grade 1200 and 1400 at constant depth of cut, 25mm; constant speed, 45m/min; no coolant and variable feed rates from 0.2 to 0.35 mm/rev (increment of 0.025mm/rev). Metallography and X-ray diffraction technique was carried out in order to identify and quantify the microstructural phases before and after drilling. The results from the trial infer that the best way to machine ADI efficiently without tool failure is using low feeds and high speeds and without coolant

Challenges in Developing High Performance Al-Li Alloys

The goal of replacing \u27conventional\u27 Al alloys with Al-Li alloys to reduce weight of aerospace structures has had only limited success to date, despite one of the largest alloy-development programs ever undertaken. One of the reasons being, for some product forms and crack-plane orientations, fracture toughness is lower compared with conventional Al alloys due to a greater propensity for low-energy intergranular fracture. Proposed explanations for brittle intergranular fracture include: (i) planar slip resultingin high stresses where slip bands impinge on grain-boundaries, (ii) embrittlement due to alkali-metal-impurity phases, and (iii) grain-boundary structural changes associated with segregation of lithium. The present paper reviews evidence for and against these proposed mechanisms based on (i) studies of 8090 and 2090 alloys, and the more recently developed 2297 alloy, and (ii) comparisons of fracture of these alloys with other materials that exhibit grain-boundary weakness. It appears that lithium segregation to grain boundaries is the prime cause of low-energy intergranular fracturein Al-Li alloys. Embrittlement by alkali-metal impurities is not important providing that impurity levels are less than about 5 ppm (as is the case for most commercially produced alloys). Planar slip and other factors probably play only a minor role

Effects of Increasing Feed Rate on Tool Deterioration and Cutting Force during End Milling of 718Plus Superalloy Using Cemented Tungsten Carbide Tool

Understanding how feed rate (ft) affects tool deterioration during milling of Ni-based superalloys is practically important, but this understanding is currently insufficient. In the present study using a 718Plus Ni-based alloy and cemented tungsten carbide tool inserts, milling experiments were conducted with ft = 0.10 mm/tooth under either dry or wet (with coolant) conditions. The results are compared to those based on using ft = 0.05 mm/tooth from previous studies. The milling force (F) was monitored, the cutting tool edge was examined and the flank wear (VBmax) was measured. As would be expected, an increase in ft increased F. It was found that F correlated well with VBmax for the high ft (0.1 mm/tooth) experiments, as opposed to the previously observed poor F-VBmax relationship for the lower ft (0.05 mm/tooth) value. This is explained, supported by detailed failure analysis of the cutting tool edges, by the deterioration mode to be dominantly edge chipping with a low occurrence of fracturing along the flank face when the high ft was used. This dominancy of the deterioration mode means that the tool edge and workpiece contact was consistent and thus resulted in a clear F-VBmax relationship. A clear F-VBmax relationship should then mean monitoring VBmax through monitoring F is possible

Characteristics of electron beam welded Ti & Ti alloys

Similar and dissimilar butt joint welds comprising combinations of commercially pure grade 4 titanium (CP-Ti), Ti-6Al-4V (Ti-64) and Ti-5Al-5V-5Mo-3Cr (Ti-5553) were created using the electron beam process. The resultant welds were studied by means of metallography, optical microscopy, mechanical testing and scanning electron microscopy. Mechanical testing was performed on welded samples to study the joint integrity and fracture characteristics. A scanning electron microscope investigation was performed on the fracture surface to reveal their fracture modes. While all weldments were crack free and most weldments exhibited mechanical properties comparable to the base metal, negligible ductility was exhibited during tensile testing joints of Ti- 5553 welded to either Ti-64 or Ti-5553.<br /