Effect of Heat Treatment and Electric Discharge Alloying on the Tribological Performance of Selective Laser Melted AlSi10Mg

Selective laser melting (SLM) is an emerging additive manufacturing (AM) technology for fabrication of complex lightweight components along with improved mechanical properties. However, the properties are highly influenced by the continual heating and cooling during deposition, variation in local temperature, size, and shape of melt pool, and solidification growth rate. Therefore, postprocessing is very often required to control various properties of additive manufactured components. The present work investigates the influence of various postprocessing methods such as heat treatment and electric discharge alloying (EDA) on ambient and elevated temperature wear behavior of selective laser melted AlSi10Mg alloy and compared with its tribological behavior with cast AlSi10Mg. The dry wear tests were conducted using a pin on disk (POD) tribometer with EN-31 as counter body. The EDA treated SLM AlSi10Mg showed the least wear-rate and coefficient of friction (COF) at both ambient and elevated temperatures (1.05 × 10⁻⁴ mm³/Nm and 0.434 and 3.12 × 10⁻⁵ mm³/Nm and 0.531, respectively) due to its higher hardness (189.8 HV) as compared with other samples. The wear-rate and COF of cast specimen are found to be highest among all specimens at both ambient and elevated temperatures (1.34 × 10⁻⁴ mm³/Nm and 0.528 and 4.49 × 10⁻⁵ mm³/Nm and 0.724, respectively). Lower wear-rate and higher COF are observed at elevated temperature due to the excessive formation of wear-resistant oxides (Al₂O₃, SiO₂, and MgO) and glaze layers for all samples compared with ambient temperature wear behaviors of its counterparts. Abrasive wear, adhesive wear, oxidation wear, and surface delamination are the prominent wear mechanisms observed for ambient and elevated temperatures for all the specimens.