7075　aluminum　alloys　with　varying　TiC　particle　additions　were　fabricated　by　simultaneously　depositing　a　standard　7075　wire　and　a　TiC　treated　wire　at　different　wire　feed　speed　ratios.　The　effects　of　TiC　content　on　the　microstructure　and　mechanical　properties　of　7075　alloy　were　investigated.　Results　indicated　that　the　addition　of　TiC　particles　can　effectively　refine　the　grain　structure　through　heterogeneous　nucleation,　and　the　grain　refinement　effect　was　enhanced　with　increasing　TiC　particle　content　in　the　range　of　0-0.70　wt%.　Moreover,　TiC　particles　can　restrain　the　continuous　distribution　of　second　phase　at　grain　boundaries.　TiC　particles　tended　to　cluster　at　grain　boundaries　as　its　content　exceeded　0.48　wt%,　which　adversely　affected　their　beneficial　effect　on　the　improvement　of　mechanical　properties.　At　an　optimal　TiC　content　of　0.48　wt%,　the　tensile　strength　and　elongation　in　the　horizontal　direction　exhibited　remarkable　enhancements　of　27.2%　and　319%,　respectively,　compared　to　those　without　the　addition　TIC　particle.