بررسي ريز ساختار و خواص مكانيكي نانو كامپوزيت لايه اي Al-Ni-Cu توليد شده توسط فرايند نورد تجمعي

چكيده انگليسي :

Investigating microstructure and mechanical properties of Al Ni Cu nano composite produced by accumulative roll bonding Ali Shabani Ali shabani@ma iut ac ir October 02 2012 Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Degree M Sc Language Farsi Dr Mohammad Reza Toroghinejad Assoc Prof Supervisor E mail toroghi@cc iut ac ir Dr Ali Shafyei Assoc Prof Supervisor E mail shafyei@cc iut ac ir Abstract In this study accumulative roll bonding and electroplating processes were used simultaneously to produce Al Ni Cu composite Copper sheets were electroplated by nickel Then accumulative roll bonding process was done on the samples including aluminum layer nickel coating copper layer nickel coating and aluminum layer for eleven cycles successfully Peeling test was used to evaluate bonding quality of Al Cu layers in the presence of nickel coating During peeling tests the effect of different parameters on the bonding quality of layers was examined These parameters were reduction in thickness nickel coating thickness and post rolling annealing treatment Then peeling surfaces were examined using optical and scanning electron microscopy Mechanical properties of the produced composite were tested using different tests such as tensile test three point bending test hardness test and microhardness test In order to determine fracture mechanism of samples during tensile test fracture surfaces were studied by SEM Samples were heat treated at different times and temperatures and then the formation of intermetallic compounds in different conditions was investigated Finally microstructure parameters of the produced composite were calculated using MAUD software The results showed that coating copper with nickel reduces the bond strength of Al Cu strips However by increasing the thickness of coating the bond strength was increased reaching the highest level as compared with the strips without coating Also the increase in the reduction enhanced the bond strength of the layered strips Yet a decrease in bond strength was achieved by post rolling annealing of the layered strips It was seen that by increasing the number of ARB cycles the bending strength of produced composite was increased Also it was found that when the number of cycles was increased not only elongation was increased but also the tensile strength of the composite was improved Microhardness for different elements in different cycles was also evaluated A uniform distribution of reinforcement copper and nickel in the matrix was seen after eleven cycles of ARB Also SEM fractograph of fracture surfaces illustrated that by increasing ARB cycles fracture mechanism was changed from ductile to shear ductile and partially to brittle fracture in the final cycles Investigation of the effect of nickel percent in the composite showed that mechanical properties of composite were reduced in the primary cycles by increasing nickel percent However by increasing ARB cycles an enhancement was seen in the mechanical properties by increasing nickel percent The study of the effect of heat treatment at different times and temperatures showed that by increasing time and temperature volume of intermetallice compound in the composite was increased Formation of AlCu Al2Cu and AlCu3 compounds in the composite was seen using XRD and EDS tests The crystallites size measured by MAUD software for aluminum and copper after eleven cycles of ARB process reached to 97 nm and 81 nm respectively The results of measurements by rietveld method were compared with those of the other studies Therefore it was obvious that the grain size of the produced composite using ARB process is less than 100 nm Keywords Metal matrix composite Al Ni Cu Accumulative roll bonding process Electroplating nickel Layered nano composite Severe plastic deformation Mechanical properties and Microstructure

شعباني، علي

بررسي ريز ساختار و خواص مكانيكي نانو كامپوزيت لايه اي Al-Ni-Cu توليد شده توسط فرايند نورد تجمعي

كامپوزيت زمينه قلزي , آبكاري نيكل , تغيير شكل شديد