ساخت نانو كامپوزيت ريختگي زمينه Al با ذرت تقويت كننده هيبريدي Al2O3/Al3Ni به روش درجا با استفاده از فرايند ريخته گري اغتشاشي

چكيده انگليسي :

Fabrication of In Situ Aluminum Matrix Reinforced Hybrid Al2O3 Al3Ni Nano Composite by Stir Casting Method Ali Reza Najarian ar najaria@ma iut ac ir Date of Submission March 14 2012 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisors Dr Rahmatollah Emadi Assoc Prof remadi@cc iut ac ir Dr Gholam Reza Arianpour Assis Prof aryanmat@cc iut ac ir AbstractAluminum Matrix Composites AMCs are important group of advanced engineering materials Theproperties of the composites are influenced by the chemical nature of the components morphology ofparticles their spatial distribution and interface interaction The high volume fraction of a fine andthermally stable reinforcement yields good mechanical properties of the composite These materialshave developed in many industrial fields such as aerodynamic and military application because of theirparticular properties Composites usually are fabricated from matrix phase and reinforcement phase Among the industrial metals aluminum and its alloys dedicated the most applications as the matrix incomposites to itself it has high strength to weight ratio and suitable ductility In this study it wasfabricated the aluminum matrix composite with hybrid reinforcement particles of Al2O3 Al3Ni by in situprocess in liquid state The in situ fabrication technology for processing the MMCs involves a chemicalreaction resulting in the formation of fine uniformly distributed and relatively stable reinforcementswith clean interfaces NiO powder and ball milled NiO powder with different particle size throughseveral stages was injected into the aluminum melt by inert gas Argon to be occurred thealuminothermic reaction and to be achieved the in situ hybrid reinforcements in the matrix Al XAl MO XAl Al2O3 M In order to increase possibility of in situ reaction the melt was stirredby a mechanical stirrer During the experiment it was emitted a bright yellow from the furnace Thiscan be an evidence to occur of the in situ aluminothermic reaction The synthesis temperature of thereaction between aluminum and nickel oxide was predicted on the basis of Al Ni binary phase diagramand the activation energy of this reaction was determined using thermodynamical data and equations The DTA result shows that the initiation temperature of reaction is 670 C The composite slurryfounded into the metallic mould after injecting NiO powder to the melt Occurring in situ reactionbetween NiO particles and melt of aluminum leads to NiO reduction by aluminum Also released Nireacts with melt of aluminum that is led to fabrication of metallic compound Al3Ni This compound alsoacts as reinforcement in the aluminum matrix In order to characterization of fabricated compositesamples the optical microscopy Scanning Electron Microscopy SEM and Spectroscopy DispersiveAnalysis EDS was used EDS results show that alumina particles have been distributed in the matrix Also the formation of Al3Ni phase is identified by microscopic observation Performing the experimentin higher temperatures show that the wetability of NiO particles is enhanced with increasing thetemperature Also some mechanical tests such as tensile test hardness test and micro hardness werecarried out in order to characterize of hybrid particle reinforcements effects The study of properties offabricated composite samples shows that the tensile strength and hardness of these samples increasesand their elongation decreases KeywordsAMCs aluminothermic reaction in situ process hybrid reinforcement particles wetability alumina

نجاريان، عليرضا

ساخت نانو كامپوزيت ريختگي زمينه Al با ذرت تقويت كننده هيبريدي Al2O3/Al3Ni به روش درجا با استفاده از فرايند ريخته گري اغتشاشي

واكنش آلومينوترمي , واكنش درجا , قابليت ترشوندگي