سال انتشار: ۱۳۸۷

محل انتشار: دومین کنگره بین المللی علوم و فناوری نانو

تعداد صفحات: ۲

نویسنده(ها):

s Samadzadeh – Department of Materials Engineering , University of Sahand
f Abbasi – Department of Materials Engineering , University of Sahand
r Azari-Khosroshahi –
n Parvini-Ahmadi –

چکیده:

Intermetallic titanium aluminides, particularly TiAl(γ) based alloys, have received a great deal of attention as candidate materials for high-temperature applications such as aerospace and automobile industries because of their low density, high specific strength. However the poor ductility and fracture toughness at ambient to intermediate temperatures are the major obstacles for practical use of these materials [1]. Attempts adupted include techniques such as grain refinement to nano scale structure and microstructure modification [2].Mechanical alloying (MA) process has been shown to be an effective means to achieve grain refinement. During high-energy milling the powder particles are repeatedly flattened, cold welded, fractured and rewelded. True alloying among powder particles can occur only when a balance is maintained between cold welding and fracturing of particles [3]. Process control agents (PCAs) in solid, liquid or gas states are usually added to the powder mixtures to reduce the effect of cold welding. Methanol, Ethanol, Stearic acid and benzene are some of the commonly used PCAs. These adsorb on the surface of the powder particles and minimize cold welding between powder particles and thereby inhibit agglomeration [3].The study aimed to investigate the structural evaluation of the powders during MA process and also after annealing treatments of mechanically milled powders. The effect of various factors such as process control agent, vial rotation speed and ball-to-powder weight ratio, on production efficiency were studied and the optimum condition to synthesize the alloy was also determined