The　flow　stress　and　strain　rate　sensitivity　of　Cu-3.1　at.%　Sn　were　measured　at　a　strain　of　0.02　using　a　base　strain　rate　of　4　×　10-4s-1　and　temperatures　between　77　and　1000　K.　An　attempt　was　made　to　model　these　data　in　terms　of　a　total　flow　stress　composed　of　three　components　including　an　internal　stress,　an　effective　stress　and　a　stress　resulting　from　dynamic　strain　aging.　The　effective　stress　was　assumed　to　be　related　to　the　strain　rate　and　the　temperature　by　a　power　law.　The　dynamic　strain　aging　component　was　assumed　to　obey　a　modified　Harper＇s　relationship.　This　latter　requires　information　concerning　the　relaxation　time　for　Cottrell　strain　aging,　τD,　where　τD　=　τD0exp(　Q　RT).　The　pre-exponential　term　τD0　was　evaluated　from　an　aging　under　stress　experiment　while　the　activation　energy　for　strain　aging　Q　was　taken　as　the　average　(7.9　×　104　J/mol)　of　Russell＇s　measurement　and　two　new　and　independent　determinations.　The　internal　and　effective　stresses　were　determined　by　a　newly　devised　technique.　It　was　found　that　this　model　could　successfully　describe　both　the　strain　rate　sensitivity　and　the　flow　stress　up　to　500　K.　The　model　fails　above　this　temperature.　This　is　believed　to　be　due　to　a　change　in　deformation　behavior　just　above　500　K　in　which　climb　and　recovery　processes　become　dominant.　©　1983.