简介:MagnesiumalloyEZ10(Mg-RE-Zn)wasdeformedintensionattemperaturesfrom20upto520°C.Arapiddecreaseoftheyieldandtensilestrengthwithtemperaturewasobservedattemperatureshigherthan300°C.Ontheotherhand,ductilityofsamplesrapidlyincreasedinthesametemperaturerange.Lightmicroscopyandscanningelectronmicroscopywasusedtorevealthereasonforthesebehaviours.Intermetallicparticlesingrainboundariesareresponsibleforexcellentmechanicalpropertiesatlowertemperatures.Diffusionalprocessesoccurringattemperatureshigherthan300°Csignificantlyinfluencedthedeformationmechanismaswellasthefracturecharacter.
简介:Threedifferenttypesoftensilestrength(TS)980MPagradeadvancedhigh-strengthsteelsusedinautomotiveapplications,namely,980MS(martensitesteel),980DP(dualphase)and980QP(quenchingandpartitioning)steelswereexamined.ThedelayedfractureresistanceofthesteelswasevaluatedusingaU-bendtest,slowstrainratetest(SSRT)andaconstantloadtensiletest.Theresultsindicatedthatallthesteelscouldpassthe300hHClsolutionimmersiontestandnoneoftheU-bendspecimenswasfracturedinthetest.However,thesteelsexhibiteddifferentsusceptibilitiestodelayedfractureunderSSRTandtheconstantloadtensiletests.980DPexhibitedthehighestresistancetodelayedfractureamongallthesamples,while980MSwasfoundtobethemostsusceptibletodelayedfracture.