“Effect of Pre-Hole Diameter on Bushing Dimensions for Friction Drilling Process of A6063-T6 Aluminum Alloy”. Journal of Al-Rafidain University College For Sciences ( Print ISSN: 1681-6870 ,Online ISSN: 2790-2293 ) 39, no. 1 (October 10, 2021): 373–387. Accessed June 9, 2026. https://jrucs.iq/index.php/JAUCS/article/view/218.