7833

7298

كارشناسي ارشد

شناسايي و انتخاب و روش ساخت مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1391

چهارده،109ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمد حسين عنايتي

فتح ا.. كريم زاده

15/4/92

علي شفيعي، كيوان رئيسي

مهندسي مواد

ID7298

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Development of Cu Zr Al amorphous nanocomposites by mechanical alloying process Esmat Dastanpoor Email address e dastanpoor@ma iut ac ir Date of Submission January 22 2013 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M S Language Farsi Supervisor Mohammad Hossein Enayati Assoc Prof Email ena78@cc iut ac ir Abstract Amorphous alloys are promising materials for various applications because of their excellent properties such as high strength and hardness good corrosion resistance and superlative electrical and magnetic properties Among various amorphous alloys Cu Zr Al alloy system is one of the most important alloys because of suitable cost with high strength high glass forming ability and low melting temperature However Cu Zr Al amorphous alloys show little room temperature plasticity and low toughness To optimize room temperature fracture toughness a microstructure consisting of crystalline phases dispersed in the metallic glass matrix was developed The aim of this research was to synthesize Cu Zr Al Al2O3 nanocomposites using mechanical alloying MA Cu60Zr40 powder mixture was first MA d in order to synthesize Cu60Zr40 amorphous alloy Also for the studying of milling energy on amorphization reaction the Cu Zr and Al powders mixture was MA d in different mills low energy planetary mill Spex mill and high energy planetary mill Evaluation of milled powders by X ray diffractometry XRD shows that mechanical alloying in different machines did not lead to amorphization reaction even after long milling time Thermodynamic investigation on the basis of extended Miedema s model in ternary Cu Zr Al system illustrated that there is a thermodynamic driving force for formation of amorphous phase in this system which is in contrast with experimental results This discrepancy was attributed to the presence of high amount of impurities including oxygen and nitrogen in Zr powder that prevents amorphization reaction Mechanical alloying of Cu60Zr40 and Cu50Zr43Al7 were repeated using higher purity Zr leading to the formation of amorphous structure with ZrO2 phase after 40 h milling In addition Cu60Zr40 and Cu50Zr43Al7 were prepared by induction melting and then milled for 10 h The results showed that a fully amorphous Cu60Zr40 and Cu50Zr43Al7 alloys are obtained Also milling of Cu60Zr40 prepared by induction melting with Cu Al and CuO powders mixture led to formation of Cu62Zr32Al4 10 V Al2O3 nanocomposite with Al2O3 particles size of about 25nm The hardness and elastic modulus of this nanocomposite were about 837 Vickers and 95GPa Keywords Cu50Zr43Al7 alloy Amorphous materials Mechanical alloying Nanocomposite PDF created with pdfFactory trial version www pdffactory com

محمد حسين عنايتي

فتح ا.. كريم زاده

علي شفيعي، كيوان رئيسي