Materials Science

Aluminum is the one of the most commonly used metal due to its mechanical properties like light weight, corrosion resistant and ductility,etc. In situ synthesis of aluminum matrix composites (AMCs) has become a popular method due to several advantages over conventional stir casting method. In the present study, AA7075/ZrB2 AMCs reinforced with various content of ZrB2 particulates (0, 3, 6and 9 wt.%) were synthesized by the in-situ reaction of molten aluminum with inorganic salts K2ZrF6 and KBF4 in order to increase its highly covalent refractory ceramic material content.
Which is then undergone wire cut electrical discharging machining experiment using 0.25 mm diameter copper wire (Brass coated) .The important machining parameters of EDM which affecting on the performance parameters are pulse on time, pulse off time, Wire feed rate, gap voltage and weight compositions of AA7075/ZrB2 .
Taguchi design of experiments is used to conduct experiments by varying the pulse on time and pulse off time. The process performance is measured in terms of Material Removal Rate (MRR), KERF Width and Surface Roughness (Ra)

Asphalt oxidative aging is one of the prevalent causes of pavement distresses which increase pavement susceptibility to fatigue and low temperature cracking. This phenomenon is mainly studied through oxidation kinetics and through evaluating oxygen diffusivity rate into asphalt binders. While oxidative aging in pavement is inevitable, application of anti‐aging additives shown to be an effective method in delaying oxidative aging. As such this paper investigates the merit of application of nano‐silica as an anti‐aging additive. To do so, different percentages of nano‐silica was added to neat asphalt binder. Asphalt binder was then exposed to short term oxidative aging using a rolling thin film oven (RTFO). To study the change in the chemical, rheological and morphological properties of asphalt binders in presence of nano‐silica, the Superpave™ tests, Fourier transform infrared spectroscopy (FTIR) as well as SEM imaging were conducted. The FTIR study shows that nano‐silica can improve the aging resistance of the asphalt binder as reflected in lower level of carboxylic acids (observed at 1400‐ 1440 cm‐1) and sulfoxide (observed at ~1050 cm‐1) in nano‐ silica modified specimen compared to those in non modified specimens. Carboxylic acids occur naturally in asphalt; however its concentration has been known to be increased significantly due to oxidative aging. This in turn reduces oxidation aging in modified asphalt. In addition, it was found that presence of nano‐silica significantly increases the complex modulus (G*) and complex viscosity (η*) of the asphalt binder. This in turn improves pavement resistance to rutting. It was concluded that introduction of nano‐silica to asphalt binder can improve the anti‐aging property, rutting performance and rheological properties of asphalt binder.