اسم المؤلف:
وليد تركي راشد
اسم المشرف:
احمد علي اكبر اكبر | هجران زين العابدين
المستخلص:
تم في هذا البحث دراسة مقاومة البلى لمواد متراكبة معدنية ذات اساس من الالمنيوم (Al - 4%Cu) باستخدام جهازذو ترتيبة المسمار على القرص (Pin on Disk) وتحت ظروف اختبار مختلفة هي (الحمل المسلط , نسبة اضافة دقائق كاربيد السليكون ,سرعة الانزلاق , زمن الانزلاق).حيث | In this research (study) wear resistance of composite materials based on metal, aluminum (Al - 4%Cu), has been studied under different test conditions (applied load, the proportion of added silicon carbide particles, a speed of sliding, sliding time) using a pin on the disk technique. Composite materials prepared using stir casting method, where vortex technique help to draw the ceramic particles into the molten metal and distributed uniformly. The composite materials containing 4 wt% Cu and 1 wt% Mg, reinforced with different proportions wt% SiC (3,6,9,12) were cast in a metal mold. Magnesium was added to improve the wetability between SiC particles and the aluminum matrix. The base alloy and composite materials samples were tested to investigate microstructure, phases, and properties using Optical Microscope, X - Ray Spectrometer, Vickers Hardness, and Scanning Electron Microscope. The optical microscope and scanning electron microscope (SEM) are also used to study the effect of loads on the worn surface. From the results of microscopic examination on found that the alloy structure of the foundation is a fine dendrite structure (Dendrite), and after the addition of ceramic particles leads to an improvement in microstructure, in addition to distributed almost homogeneous in the matrix and on the boundaries crystalline. X - ray diffraction examination approved the existence of aluminum and silicon carbide phases. In addition to the deposition phase (Al2Cu) because of the natural aging,(Mg Al2Cu) phase and the presence of this freak indicate on the interaction of aluminum with the added elements, The hardness test results show that, the increasing the ceramic particles proportion tend to increase the hardness, the highest hardness found at 12wt% SiC. By studying the worn surface, using optical microscope and SEM, increasing in wear was observed with applied load for all reinforced particles percentage added. With the increased load, more wear, deep, and closed paths was formed. Twotypes of wear were monitored at high loads, adhesive wear and abrasive wear. The studying of wear rate for both base alloy and composites materials with various conditions, show that wear rate increase with increasing applied load, but the composite materials show higher wear resistant. The best wear resistance found at 12 wt% SiC addition.The studying of sliding speed show that the wear rate decreases with high speed the for both base alloy and composites materials. The sliding time show direct correlation with wear rate, but at continuous increasing sliding time, wear rate decline constantly.Statistical methods with software (Minitab 15) was used to study the effect of wear on weight loss for both the base alloy and composite material by using three variables; ( applied load (X1), silicon carbide proportion (X2), sliding distance (X3), with five levels of each variable. It was concluded that the optimum weight loss (Optimization of weight loss) (0.0046 g), as a result the wear process, are found at the these following levels of variables; applied load (2.5 N), sliding distance (7.2 Km) and at the silicon carbide proportion (3.6364 wt% Sic). Equation describes the combined effect of variables and the weight loss was obtained and which variable are more influential. Y = 0.010180 + 0.002825 X1 - 0.002375 X2 + 0.001100 X3 + 0.001809 X32 + 0.004700 X1 X3 + 0.002700 X2 X3 The applied load (X1) and sliding speed (X3) both have the largest effect on weight loss. Both, applied load and silicon carbide does not have any effect on the weight loss. For individual variable, it foundthat applied load has the greatest influence on weight loss.
