176 FORMATION OF SUPERSATURATED (TI, AL)N SOLID SOLUTION BY HIGH ENERGY BALL MILLING OF TIN-ALN POWDERS. Radune M 1,2,* ., Zinigrad M 1 . and Frage N 2 . 1. Ariel University, Kiryat Hamada 1, Ariel 40700, Israel 2. Department of Materials Engineering, Ben-Gurion University of the Negev, P.O.B. 653 Beer-Sheva 8410501, Israel Abstract In the present study (Ti,Al)N nano-size powders with various fraction of AlN were synthesized from the mixtures of TiN and AlN powders by mechanical alloying using a planetary high energy ball milling (HEBM). X-ray diffraction (XRD), energy-filtered transmission electron microscopy spectrum imaging (EFTEM) and energy dispersive x-ray spectroscopy (EDS) confirm the formation of the (Ti,Al)N supersaturated solid solution (up to 50 mole%AlN). The crystalline size of the mechanically alloyed powders after 100 hours of milling is about 13nm. Keywords Mechanical alloying, high-energy ball milling, supersaturated solid solution, titanium nitride, aluminum nitride. 1. Introduction Supersaturated titanium-aluminum nitride ( N Al Ti x x 1 ) is very attractive material for a wide range of applications due to its high oxidation and wear resistance accompanied by high strength, hardness, thermal conductivity and thermal shock resistance [1-4]. Currently, the applications of N Al Ti x x 1 are limited to coatings, with a thickness less than m 10 , obtained by physical or chemical deposition [1, 5-7]. Bulk materials based on supersaturated N Al Ti x x 1 solid solution was also fabricated by powder metallurgy approach, which involves preparation of N Al Ti x x 1 powder and its consolidation [8-10]. N Al Ti x x 1 powder may be synthesized by mechanical alloying (MA) through a solid-gas reaction in a nitrogen atmosphere using high energy ball milling (HEBM) approach [8, 9]. Ti powder and Ti 50 Al 50 powder mixture were successfully nitrided to form TiN and solid solution (Ti 50 Al 50 )N with NaCl-type structure [8]. In [9] Ti 100-x Al x (x≤50) mixtures were also nitrided completely to form a solid solution N Al Ti x x 1 . In [10] TiH 2 and Al mixtures were used as starting materials for synthesis N Al Ti x x 1 powder under nitrogen media using HEBM. Du et al.[11] have applied HEBM in order to treat AlN, Ti and ammonium carbonate powders. Kim et al. [12] have tried to obtain N Al Ti x x 1 powder from mixtures of pure nitrides using HEBM, however, milling at 250rpm for various durations (up to 40h) did not lead to the formation of solid solutions. Despite this fact, in the present study we have tried to find the parameters of HEBM for successful fabrication of N Al Ti x x 1 powder from the mixtures of pure nitrides. 2. Materials and Methods TiN and AlN both grade C (Starck H.C.) micron size powders, supplied by Starck H.C. company, were used as starting materials. Various powder mixtures (10, 20, 30 and 50mole % of
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176
FORMATION OF SUPERSATURATED (TI, AL)N SOLID SOLUTION BY
HIGH ENERGY BALL MILLING OF TIN-ALN POWDERS.
Radune M1,2,*
., Zinigrad M1. and Frage N
2.
1. Ariel University, Kiryat Hamada 1, Ariel 40700, Israel
2. Department of Materials Engineering, Ben-Gurion University of the Negev, P.O.B. 653 Beer-Sheva
8410501, Israel
Abstract In the present study (Ti,Al)N nano-size powders with various fraction of AlN were
synthesized from the mixtures of TiN and AlN powders by mechanical alloying using a planetary
high energy ball milling (HEBM). X-ray diffraction (XRD), energy-filtered transmission electron
microscopy spectrum imaging (EFTEM) and energy dispersive x-ray spectroscopy (EDS)
confirm the formation of the (Ti,Al)N supersaturated solid solution (up to 50 mole%AlN). The
crystalline size of the mechanically alloyed powders after 100 hours of milling is about 13nm.