5910

5525

كارشناسي ارشد

ريخته گري

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1389

چهارده،131ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمدحسين فتحي، بهزاد نيرومند

25/2/90

علي شفيعي، حسين ادريس

مهندسي مواد

ID5525

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Effect of Nano Ceramic Coatings on Casting Microstructur and Mechanical Properties of Thin Wall Aluminium Castings Mansour Borouni Mahmoud Salehi m mahmoudsalehi@ma iut ac ir Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Degree M Sc Language FarsiDr Mohammad Hosein Fathi Prof Supervisor E mail fathi@cc iut ac irDr Behzad Niroumand Assoc Prof Supervisor E mail behzen@cc iut ac irAbstractGravity casting is a popular method for production of complex thin wall castings In gravity castingmethod of thin wall castings the melt that filling the mould with effect of self weight doesn t havesufficient fluidity consequently causing defects sach as cold shut misrun and shrinkage defectsduring the solidification The mentioned defects reduces quality and mechanical properties of thinwall casting parts The use of aluminium thin wall castings in production of aluminium parts isnecessary not only for reduction of the part weight but also for achievment an appropriate weight tostrength ratio Most of thin walled parts used in the aircraft manufacturing industries are producedunder class A1 military standard sach as MIL STD 2175A and should be free from any defect Amajor issue in different thin wall casting parts is castability which includes the melt fluidity pouring temperature alloy composition type and quality of applied coatings on sand mold areamong the most important factors affecting fluidity This study investigated the effects of ceramiccoatings containing nano particles on the fluidity length microstructure and mechanical propertiesof thin wall aluminum parts produced by gravity casting method in sand moulds For this purpose a special pattern with different section thicknesses proportional to the thickness of aerospacecomplex parts was designed and built for fluidity test By changing the type of mould coating including graphite coating micro ceramic coating and nano ceramic coatings samples of AL4 1aluminum alloy were gravity cast Casting fluidity lengths in each sample was measured andmicrostructure and mechanical properties were examined and compared The comparison showedthat the fluidity and castability were improved in moulds coated with three type of nano ceramicmold coatings Micro ceramic mould coating had better results than the sand mold without coating the sand mold with graphite mold coating or sand mold with micro ceramic mold coating Radiographic studies assisted showed that samples cast in the uncoated sand mould graphitecoating sand mold and micro ceramic coating sand mold had some internal defects sach asshrinkage cavity shrinkage sponge gas hole and gas porosity While the samples cast in sand moldwith nano ceramic coatings had higher soundness and producing of class A1 aluminum castingsusing nano ceramic coatings was possible Also results show that by increasing the sectionthickness and applying nano ceramic mould coatings on surface of sand mould the fluidity lengthand the quality of casting part will be improved Metallugraphy studies showed that themicrostructure and mechanical properties of the samples cast in sand mould with nano ceramiccoatings were more desireable Keywords AL4 1 aluminium alloy Nano ceramic coating Micro ceramic coating Fluiditylength Thin wall castings Mechanical properties Casting defects Radiography

محمدحسين فتحي، بهزاد نيرومند

علي شفيعي، حسين ادريس