Characterization and modeling of static recovery process of brass (Copper Zinc) alloy / Mohamad Hafizul Hisyam Bin Yahya

Project paper (Bachelor of Mechanical Engineering) -- Universiti Malaysia Pahang - 2008

Static recovery process is a process of restoration of material properties back to original state. This process only occurs just below recrystallization temperature. In static recovery condition the dislocation of material is annihilated so the internal stress of material could be released. To obtain fraction of recovery, brass will be pre strain in various amount of value before go through annealing process in various static recovery temperature. This experimental process starts with machining the specimens by using manual lathe machining. Then all the specimens will be annealed in recrystallization temperature which is 570˚C. Next process is pre strain in various pre strain performed by compression and tensile test machine. After that process, specimens will be annealed in recovery temperature which is below 290˚C. Then final pre strain will be performed to obtain yield strength of recovered material. Finally based on the experimental data Friedel’s model is used to acquire activation energy. From the calculation some of the activation energy value could be acquire such as -30 kJ/mol, 516 kJ/mol, 276 kJ/mol and 349 kJ/mol. These values of activation energy are compared with value obtained by using same method that used by Martinez which is in range of 216-357 kJ/mol. From the comparison percent of difference can be acquire. Since this percent of difference could be acquired, the significant value can be obtained and this is how Friedel’s model is validated.