International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In this study, mechanical alloying (MA) of Al-WC powder system was studied to produce aluminium composite powders having finer tungsten carbide fraction in aluminium matrix. For this purpose, elemental mixtures of 70 wt. % aluminium (Al) powder and 30 wt. % of tungsten carbide (WC) powder were mechanical alloyed for the duration of 2, 4 and 8 hrs. MA’ed powders then annealed at 300 ºC, 400ºC and 500ºC for 2 hours under inert atmosphere. Apparent densities of powders were measured in order to characterize both mechanical alloyed and annealed powders. Compressibility of the powders was determined by green density measurements after pressing.

Microstructural characterizations were conducted with X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Strain rates and crystallite sizes were measured according to fundamentals parameter approach (FPA) by applying Lorentzian function using software TOPAS 4.2.

Mixtures of 10, 20 and 30 wt. % of tungsten carbide powder and aluminum powder were ball milled for 2, 4 and 8 hrs to investigate the effect of percentages of the reinforcement and mechanical alloying time on microstructural properties of the produced composite powders. Finer particles were tried to obtain in ductile matrix. The milled powders were analyzed using X-ray diffraction (XRD).

Nano/micro particle size and distribution (PSD) technique was used to measure particle size and distribution. Scanning electron microscopy (SEM) was also performed to observe particle morphology.

With 65 wt% solid content, Polymer/YSZ composites have been produced via extruder by using of PP, PMMA and TPU. With pyrolysis process, physical stability conditions of continuous YSZ free form fibres have been investigated according to type of polymer and pre-sintering temperature. In addition to this, melt flow rate values and thermal analysis investigations of PP, PMMA, TPU, PP/YSZ, PMMA/YSZ, TPU/YSZ were determined by melt flow rate analysis and TGA. Compared to unreinforced polymers (PMMA, PP and TPU) the melt flow rate of the composites containing YSZ powder has decreased approximately 15 %. From TGA results it was also found that the contribution of the yttria stabilized zirconia changed the decomposition temperature of the polymer part.

Ni-Ti system is an interesting binary system having different intermetallic compounds. NiTi is the one of them having commercial importance because of its shape memory and superelastic characteristics. In this study, effect of mechanical alloying was studied against milling time to observe powder state changes and phase formations. 35Ni-65Ti, 45Ni-55Ti and 50Ni-50Ti compositions in Ni-Ti binary system were selected, It was possible to obtain different intermetallic compounds in Ni-Ti binary system by mechanical alloying of initial Ni-Ti powders. It is also observed that, particle size and distribution measurements, XRD phase analysis, density measurements and morphological evaluation of the mechanical alloyed powders can be used for the determination of optimum conditions for obtaining desired level of alloying and final product.