Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Al-In monotectic alloys are potential alternatives for application in the manufacture of wear-resistant automotive components, such as cylinder liners and journal bearings. The comprehension regarding the development of distinct microstructures of monotectic alloys and their interrelation with wear behavior are challenges of prime importance. The present study aims to contribute to a better understanding of the relationship between the scale of the minority phase of the monotectic microstructure and the corresponding wear behavior. Transient directional solidification experiments were carried out with an Al-5.5 wt% In alloy with a view to provide samples with significant differences in the microstructural scale along the casting length. The results of wear tests permitted an experimental quantitative expression correlating the wear volume (V) with both the interphase spacing between indium droplets (lambda) and time of wear tests (t) to be proposed. The increase in lambda is shown to improve the wear resistance. The effect of lambda on V becomes more significant as the sliding distance (or time) is increased. (C) 2013 Elsevier Ltd. All rights reserved.66182186Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)