This work aims to characterize and compare the coefficient of friction (CoF) and wear rates of some metallic materials (AISI 6061-T6 alloy, AISI 316 L stainless steel and ASTM F1537 CoCrMo alloy) ...under different wear modes, namely, micro-abrasion abrasion (rolling and mixed rolling/grooving abrasion), and wet and dry sliding abrasion. The wear modes were achieved by conducting testing under muddy environment at different SiC abrasive particles concentration and wet and dry conditions at three different loads (1, 2 and 3 N) using an instrumented micro-abrasion tester. Wear volumes were measured by optical profilometry to estimate wear rates, while wear patterns were visualized in detail by SEM. CoF, wear rate and mode results for all materials and conditions are reported and discussed. Wear modes were found to have a considerable effect on CoF and wear rate for the materials. Pure rolling abrasion generated the highest wear rates for all materials. Mixed rolling abrasion/grooving produced higher CoFs, but lower wear rates than those produced by pure rolling abrasion. Wet sliding promoted the highest CoFs for AISI 316L SS and AISI 6061-T6 meanwhile dry sliding generated the lowest CoFs and wear rates.
In this paper, authors present a study of the application of speckle shearing interferometry (shearography) and digital image correlation to measure viscoelasticity in terms of creep compliance of ...elastomeric materials. The creep tests were performed using two different elastomers (neoprene and EPDM) by applying a constant tensile stress to a specimen during 3 h. First, a shearography setup was implemented to measure directly the in-plane strains produced in the specimens and thus determining creep strains. Secondly, digital image correlation was also used to measure the creep strains in similar creep tests. The results obtained were compared each other to see the effectiveness of each measurement technique for the assessment of this property. It was demonstrated that these techniques can be potentially and successfully applied to the creep analysis of these kind of materials. Moreover, advantages and drawbacks of both measurement methods are discussed.
•An accelerated test to evaluate crevice corrosion in joints is presented.•The joint study case (cylinder head, gasket and mono-block) was studied.•Three aluminum alloys from different cylinder heads ...were evaluated.•Corrosion rates, crevices volume and potentiodynamic behavior were obtained.
A test to evaluate crevice corrosion in joints of mechanical components sealed with composite structure gaskets in corrosive environments is presented. The crevice corrosion produced in joints comprising the cylinder head, gasket and mono-block was aimed as a study case to illustrate the test. It is based on polarization resistance and potentiodynamic polarization measurements obtaining localized and measurable crevice corrosion on small specimens in a short time. Corrosion rates, crevices volumes and potentiodynamic behavior of assembly specimens made of three different aluminum alloys extracted from actual cylinder heads and mono-blocks, and sections of cylinder head gasket were obtained and reported.
The solubility of automotive elastomers, namely, silicone rubber (VMQ), flouroelastomer (FKM) and ethylene-propylene-diene monomer (EPDM) in Jatropha bio-based lubricant (bio-oil), an engine mineral ...oil (EMO) and a blend of the bio-oil with EMO, respectively, was analyzed by using the Hansen solubility method. In addition, an experimental compatibility analysis, consisting on standard immersion tests and measurements of changes in mass, volume, hardness and tensile and tear strengths, was conducted to complement and validate the results obtained using the Hansen method. The Hansen method was found to be in good agreement with the compatibility tests and provided an appropiate description of the dissolution/degradation behavior of the seals upon exposure to the lubricants. Finally, it was found that FKM was the most compatible in the three lubricants, while EPDM was very prone to dissolution/degradation in EMO and B20, and VMQ in the bio-oil.
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