The Effect of Adding Alumina Phases (alpha and amorphous) to Improve the Mechanical Properties (Compressive Strength and Hardness) of Polyester Matrix Composites. J. eng. sustain. dev. 2014;18(6):202-211. تاريخ الوصول مايو 19, 2024. https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/931