简介:Themicrostructureandmechanicalpropertiesoffrictionstirwelded2.5mm7050-77451aluminumalloynaturalaging72hand17520hwereinvestigated,respectively.Theuniaxialtensiletestshowedthatyieldstrength,tensilestrengthandelongationofthejoints17520hnaturalagingwereabout20%,12%and24%higherthanthosejointsnaturalaging72h.Hardnessprofileofnaturalaging17520hjointwitnessedsignificantenhancementinnuggetzone,comparedwith72hnaturalaging.Differentialscanningcalorimetry(DSC)andtransmissionelectronmicroscopy(TEM)testrevealedthatmoreGuinier-Prestonzone,η'andηphaseemergedinnuggetzoneasnaturalagingdurationincreased,highdensityofdislocationlocatedwithingrainboundaryinnuggetzoneofjointsnaturalaging72h.ItisconcludedthatnaturalagingwasfeasibletoenhancestrengthandplasticityofFSWjointssimultaneously.
简介:Stationaryshoulderfrictionstirlapwelding(SSFSLW)wassuccessfullyusedtoweld6005A-T6aluminumalloyinthispaper.EffectofpinrotatingspeedoncrosssectionmorphologiesandlapshearstrengthoftheSSFSLWjointsweremainlydiscussed.Resultsshowthatjointswithoutflashandshouldermarkscanbeobtainedbythestationaryshoulder.CrosssectionoftheSSFSLWjointpresentsabasin-likemorphologyandlittlematerialloss.Byincreasingtherotatingspeedfrom1000rpmto1600rpm,botheffectivesheetthicknessandlapwidthincrease,whilelapshearfailureloadfirstlydecreasesandthenincreases.Themaximumfailureloadof14.05kNisattainedwhen1000rpmisused.AllSSFSLWjointspresentshearfracturemode.