تاثير انرژي فرايند آسياب كاري بر مكانيزم تشكيل تركيبات بين فلزي نانو ساختار Ni-Ti و مشخصه يابي پوشش هاي پاشش پلاسمايي حاصل از آن

چكيده انگليسي :

115The Effect of Energy System Impact in Mechanical Alloying MA on the FormationMechanism of Nanostructure Intermetallic Ni Ti Alloys and Characterization of ItsPlasma Spray Coatings Mansoor Toorani Farani m tooranifarani@ma iut ac ir Date of Submission 19 5 2012 Department of Material Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mehdi Salehi Surfacesalehi@hotmail com HoseinEdris h edris@cc iut ac irAbstractIntermetallic compounds have certain properties that distinguish them from other intermetallic compounds Theseproperties include shape memory compatibility with body environment super elasticity property high toughness appropriate tribology behavior and high corrosion resistance Given their properties Ni Ti intermetalliccompounds are extensively used in the medical industry aerospace industry and surface engineering Ni Ti systemhas 3 intermetallic compounds including Ni3Ti NiTi NiTi2 NiTi intermetallic compound has receivedsufficient attention in different studies but the other two compounds seem to be partially neglected in previousresearch Several methods such as metallurgy powder SHS mechanical alloying and explosive shock are used toproduce Ni Ti intermetallic compound Mechanical alloying has recently been introduced as one of the latestmethods for producing Ni Ti alloys in powder form and as an alternative to conventional melting and castingtechniques and SHS One advantage of this method is the production of nanostructure materials Despite somelimitation because of low production cost and simple process mechanical alloying MA is one of the bestmethods for making and production intermetallic compounds Firstly this study investigated production ofnanostructure Ni75Ti25 powder through mechanical alloying using two kinds of high energy planetary ball milland attritor under argon atmosphere Microstructure investigations were made by X ray diffraction XRD Scanning Electron Microscope SEM thermal analysis and microhardness surveys The results showed thatalloying Ni75Ti25 powder mixture leads to the formation of solid solution and some Ni3Ti phase The mechanismfor the formation of this compound begins by the formation of layered structure of raw materials and titaniumatoms in nickel dissolution Continuing process of supersaturated solid solution Ni3Ti structure is provided Afterheat treatment higher order Ni3Tiand greater presence of this compound will be observed Super lattice peaks instructure of powder do not occur in any parts of the mechanical alloying and heat treatment process Initialdevelopment of Nickel Titanium compounds has been caused due to their shape memory property super elasticbehavior energy absorption capability and biocompatibility But research in the last two decades has indicated thatthese compounds resist abrasion erosion corrosion cavitation and erosion corrosion resistant as well As such this study also investigated the coating of a powder mixture Ni75Ti25 Atmospheric plasma spraying APS method was used to create intermetallic coatings of nickel titanium on carbon steel The given powder wasgrinded for 2 hours prior to spraying Spray process was used to perform 4 different currents Amp The resultsindicated that Ni3Ti NiTi2 intermetallic phases Nickel and small amounts of titanium oxide were found in allcoatings With higher current fewer intermetallic compound formations were made leading to different propertiesin coatings Moreover the coating created with high current was denser than other coatings and having betteradhesion in substrate It was also found that harder coating had lower resistance against vickers intrusive andcracked sooner Therefore they have lower fracture toughness Keywords Ni Ti intermetallic compounds Mechanical alloying Nanostructure Materials APS

طوراني فراني، منصور

تاثير انرژي فرايند آسياب كاري بر مكانيزم تشكيل تركيبات بين فلزي نانو ساختار Ni-Ti و مشخصه يابي پوشش هاي پاشش پلاسمايي حاصل از آن

تركيبات بين فلزي نيكل-تيتانيم , آلياژ سازي مكانيكي , پاشش پلاسمايي اتمسفري