Modeling the tensile behaviour of Al-7075 composites prepared with xB4C under a high flow water cooling rate

Abstract

The choice of stir casting has attracted interest among researchers in the development of boron carbide-Al 7075 composites. Most literatures focus on stir casting parameters like stirring temperature, speed, and time with few or no studies on cooling rate which is the last and very essential stage of the process. In this investigation, boron carbide (B4C) was introduced in Al-7075 at constant stirring parameters with varying water cooling rates. The two variables used are A and B for boron carbide dosage (5, 10, 15 wt. %) and water flow rate at room temperature (100, 300, and 500 cm3/s), respectively. The result showed that dosages of 5 to 10 are dispersed within the matrix resulting in enhanced strength while 15 wt. % resulted in particle clustering, thereby leading to depreciation of strength. Meanwhile, increasing the water cooling rate brought about grain refinement which led to improved tensile properties. However, at 500 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>/s it resulted in the storage of residual stress, which was detrimental to the strength values. At 5 - 15 wt. % and 100 - 500 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>/s, it amounted to a consecutive decrease in elongation. The statistical analysis showed that the experimental variables significantly affected the tensile properties. From the regression models developed, there were good representations of the data and are statistically fit in predicting the responses. The Optimum condition stipulated was 11.7414 wt. % B4C and 329.7 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>/s.