Comparative study of Aluminum alloy, Gray CI, structural steel and Low alloy steel AISI 4140 spur gears using FEA and material testingJawahar Nishit Kumar, Gokula Krishnan Agilan, Sanjay Natarajan and Sundaramali GovindaswamyEPJ Web Conf., 354 (2026) 01010DOI: https://doi.org/10.1051/epjconf/202635401010