بررسي تاثير الگوي سطح بر روي استحكام چسبندگي پودر به آلومينيوم در دوفلزي آلومينيوم

چكيده انگليسي :

Study of Surface Pattern Influence on Bonding Strength of Powder to Aluminum in Al Al Sio2 Nanocomposite Bimetal Mojtaba Sadegh Mojaba sadegh@me iut ac ir Date of Submission 2019 07 01 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Abbas Ghaei Ghaei@cc iut ac irAbstract Bimetals are widely used in various industries including aerospace military marine and infrastructure Inthese industries materials with high strength to weight ratio are required Aluminum is one of the most widelyused metals due to its certain properties such as low weigh high electrical and thermal conductivity andcorrosion and wear resistance Powder solid bimetals made up of metal sheets and ceramic powder are popularbecause of combination of the properties high formability and ceramics high young s modulus Incomparison to macro scale powder nanoscale powder generally yields more desirable mechanical properties Adhesion of powder to bimetal strips is essential in creating the integrity of structure and desired properties ofthese materials In this study the effect of creating grooves with different shapes and patterns on the surfaceof aluminum strips in bimetal aluminum aluminum powder nanosilica on adhesion of powder to strip wasinvestigated To create adhesion aluminum oxide layer that is naturally formed on the surface of aluminumshould be removed Grooves can help break the oxide layer and improve adhesion through creating stressconcentration points Therefore in this study groove with different shapes and patterns were modeled on thesurface using Abaqus finite element package As the samples are pressurized during compaction a pressureboundary condition was enforced on the surface of strips Using the simulation results the grooves on whichthe longitudinal tensile stress in the oxide layer was higher than the ultimate tensile strength of alumina wereselected for experimental testing The selected grooves were created on the surface of aluminum strips throughthe machining process 1WT of nanosilica powder were mixed with pure aluminum powder using a planetaryball mill at 250 rpm for 2 hrs The powder was then placed between aluminum strips and compacted under 200MPa pressure The specimens were then sintered for 1 hr at 600 C in a furnace with Argon atmosphere Theadhesion was evaluated by peeling test according to ASTM D1876 01 The effect of type depth and density number of grooves in 4 mm length of grooves on the adhesion force was studied and the optimum patternwas introduced The results were analyzed by observing the images of microstructure The results showed thatthe simulation results are qualitatively in good agreement with the experimental results The uniaxial stress strain curves of the samples were obtained using uniaxial tensile test according to ASTM E8 and the effect ofdifferent groove patterns on the mechanical properties was studied It was also observed that samples thatexhibit greater adhesion in peeling test have a higher tensile strength The groove pattern with density of 3 depth of 0 8 mm and shape of square was found to be optimal among the samples in terms of the adhesionforce Keywords Aluminum matrix nano composites Solid nanopowder bimetals Adhesion Surface patterns

صادق، مجتبي

بررسي تاثير الگوي سطح بر روي استحكام چسبندگي پودر به آلومينيوم در دوفلزي آلومينيوم - نانوكامپوزيت Al-SiO2

نانوكامپوزيت زمينه آلومينيوم , دوفلزي جامد - نانوپودر , چسبندگي , الگوي سطحي