材料科学英语Unit 1 Lecture 4 Critical thinking.ppt

CriticalthinkingUnit1Unit1

CriticalThinking1Unit1double-shellstampedaluminumdoorstheDoorsClosuresInnovationAward,2011morethan20%ofthebodystructure

Materialsscientistsandengineershavetopreparefortheconstantchangesinmaterialsusage.Nowyourtaskistocomparethetwopicturesandanswerthefollowingquestionsingroups.1.DescribethechangeofmajormaterialsusedinproducinganautomobileintheUSfrom1997to2015.2.Giveanotherexampleofchangesofmaterialsusedinsomemanufacturedproductsoveraperiodoftime.3.Whatfactorsmaymotivatethedevelopmentandapplicationofnewmaterials?CriticalThinking

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Unit1CriticalThinkingFerrous50-60%(15-20%HighStrengthLowAlloySteel)OtherPlastics10-20%Aluminum5-10%1

CriticalThinkingUnit11

ThechangeinmaterialsusageisevidentinthecompositionoftheU.S.auto.In1997theaverageU.S.autoweighed1,476kgandplasticscomprisedover10%ofitwhileferrousincludingaround15%HSLAmadeupover50%.The2015U.S.auto,bycomparison,weighedanaverageof1,225kgandconsistedof9.3%plastics,43.7%steel(mildsteel,mediumandconventionalhighstrengthsteelandothersteels),6.2%iron,10.3%MHSS,CHSSandAHSS,0.6%Magnesiumandothermaterials.Thetrendintheusageofmaterialsappearstobemoresteelinautosandlesscastiron.Newmaterialsarealsoappliedtothemanufactureofautostomakethemlighter.CriticalThinking1Unit1

CriticalThinking2Unit1

Factorstomotivatethedevelopmentanduseofnewmaterialsinclude:demandfornewproductswithuniqu