Discharge　voltage　is　one　of　the　most　important　parameters　in　electromagnetic　riveting.　The　effect　of　discharge　voltage　on　the　deformation　of　Ti　Grade　1　rivet　was　investigated　by　experiment　from　macro　and　micro-scales　in　low　voltage　electromagnetic　riveting.　The　result　shows　that　the　amplitude　of　the　discharge　current,　the　riveting　force　and　the　rivet　deformation　increases　with　the　discharge　voltage.　The　deformation　in　the　rivet　head　is　inhomogeneous　and　there　are　three　deformation　zones,　viz.,　large,　small　and　difficult　deformation　zones.　The　deformation　in　rivet　shaft　is　quite　uniform.　The　deformation　of　Ti　Grade　1　rivet　is　an　adiabatic　process　and　the　deformation　mechanism　is　adiabatic　shearing　deformation.　With　the　increase　of　discharge　voltage,　adiabatic　shear　band　gets　more　and　more　obvious　and　the　grains　inside　the　adiabatic　shear　band　are　elongated　severely　and　re-arranged　along　the　direction　of　the　adiabatic　shear　band.　A　model　for　the　modeling　of　grain　deformation　inside　the　adiabatic　shear　band　is　proposed.　When　the　adiabatic　temperature　does　not　affect　the　flow　of　the　material,　the　process　of　microstructure　evolution　mechanism　of　Ti　Grade　1　rivet　in　electromagnetic　riveting　is　mainly　the　twinning　deformation.　With　the　increase　of　rivet　deformation,　it　is　the　sub-grain　rotation　to　complete　the　dynamic　recrystallization.　These　findings　provide　an　in-depth　understanding　of　Ti　Grade　1　rivet　deformation　mechanism　and　a　basis　for　process　determination　and　quality　assurance　of　the　electromagnetic　riveting　process.　(C)　2013　Elsevier　B.V.　All　rights　reserved.