3475

3281

كارشناسي ارشد

خوردگي و حفاظت از مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1385

هشت، 124، [I] ص.: مصور، نمودار، جدول

ص. ع. به فارسي و انگليسي

فتح اله كريم زاده، بهزاد نيرومند

محمدعلي گلعذار

15/2/86

محمدحسين فتحي، عبدالمجيد جعفري

1396/02/30

كتابنامه

مواد

مهندسي مواد

ID3281

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

126AbstractOne of the processes for production of material used in thixoforming process is strain inducedmelt activation SIMA process In this research effect of thixoforming process onmicrostructure mechanical properties fracture mode and corrosion behavior of A356thixoformed alloy produced by SIMA process was investigated Based on the results acombination parameter in the name of silicon particle appearance index SPA index wasintroduced This parameter relates the mechanical properties and fracture mode of A356thixoformed alloy samples to circle equivalent diameter elongation and spacing of siliconparticles dispersed in the microstructure of the alloy According to this parameter thixoformedsamples with lower SPA index have higher mechanical properties especially tensileelongation in comparison with as cast sample with higher SPA index Results of fractographicexaminations showed that damage in as cast sample with high SPA index is generated bycracking and debonding of silicon particles from particle matrix interface On the contrary damage in thixoformed samples is generated only by silicon debonding from matrix Resultsshowed that SPA index did not predict alone the mechanical behavior of thixoformed samplesthat ones have been subjected to T6 heat treatment Using obtained results is cleared thatthixoforming process has been caused that enhancing of silicon particles compactness Inorder to relate the compactness parameter to pitting corrosion resistance a microstructuralparameter is introduced According to this parameter samples that have silicon particles withhigh compactness consequently have higher corrosion resistance Results of galvaniccorrosion test showed that increasing the silicon particles compactness leads to reduce thegalvanic corrosion current density between silicon matrix galvanic couples As a result thixoforming process because that changes the morphology of silicon particles from acicularto circle shape is caused the enhancing of pitting corrosion resistance of A356 thixoformedalloy According to obtained results if thixoforming process caused the enhancing siliconparticles compactness pitting corrosion resistance increases 126

فتح اله كريم زاده، بهزاد نيرومند

محمدعلي گلعذار

محمدحسين فتحي، عبدالمجيد جعفري