Page - 32 - in 3D Printing of Metals

Metals 2017,7, 2 processing andpowder properties. This remains an open research area due to the large number ofprocess/designparameters (e.g., laserpower, traverse speed,powder feed rate, layer thickness, hatchingpitch, scanningpattern,etc.) involvedduringSLM.Mostof theexistingstudieshavesought onlyoptimalprocessparametersviaextensiveexperimentalwork.Amajor limitationof thisapproach is that the resultingoptimalprocessparametersmaynot beusefulwhenexperimental conditions (e.g.,processormaterial) change,with theresult thatnewexperimentsneedto-be-conductedfrom scratch. Further research is needed to lever the information from similar earlier studies and to systematicallycharacterize therelationbetweenprocessparametersandpart featuresso that theSLM processcanbeoptimizedinamoreefficientmanner.Models thatcorrelateprocessingconditions to themicrostructureandqualityof thefinalproductarealsoneededtominimize thecostandtimeline associatedwithprocessdevelopment. Processspecifications for lasermeltingshouldbedevelopedto avoidtheoccurrenceofdefects toenablereliableproductionofmagnesiumalloys.Withadditional knowledgeandapplicationofspecific tailoringof theproperties, it is likely thatSLMofmagnesium alloyswill see increasedusage in forthcomingdays. AuthorContributions:VyasarajManakari andGururajParandeoutlined thereview,performedthe literature searchandwrote themanuscript.ManojGuptahelped incompiling thewide informationrelatedto the topicand datapresentationandperformedtechnical editing forall corrections.ManojGuptaalsohelped inwriting the manuscriptanddevelopedthe ideaof the topicandwasresponsible for thecorrespondence. Conflictsof Interest:Theauthorsdeclarenoconflictof interest. References 1. Gupta,M.; Sharon,N.M.L.Magnesium,MagnesiumAlloys, andMagnesiumComposites; JohnWiley&Sons: Hoboken,NJ,USA,2011. 2. Mordike,B.;Ebert,T.Magnesium:Properties—Applications—Potential.Mater. Sci. Eng.A2001,302, 37–45. [CrossRef] 3. Froes, F.; Eliezer,D.;Aghion,E.The science, technology, andapplicationsofmagnesium. JOM1998,50, 30–34. [CrossRef] 4. Winzer,N.;Atrens,A.;Song,G.;Ghali,E.;Dietzel,W.;Kainer,K.U.;Hort,N.;Blawert,C.Acritical reviewof thestresscorrosioncracking(SCC)ofmagnesiumalloys.Adv. Eng.Mater. 2005,7, 659–693. [CrossRef] 5. Song, G.L.; Atrens, A. Corrosionmechanisms ofmagnesium alloys. Adv. Eng. Mater. 1999, 1, 11–33. [CrossRef] 6. Jun, J.; Kim, J.; Park, B.; Kim, K.; Jung,W. Effects of rare earth elements onmicrostructure and high temperaturemechanicalpropertiesofZC63alloy. J.Mater. Sci. 2005,40, 2659–2661. [CrossRef] 7. Itoi,T.;Takahashi,K.;Moriyama,H.;Hirohashi,M.Ahigh-strengthMg-Ni-Yalloysheetwitha long-period orderedphasepreparedbyhot-rolling.Scr.Mater. 2008,59, 1155–1158. [CrossRef] 8. Toda-Caraballo, I.;Galindo-Nava,E.I.;Rivera-Díaz-del-Castillo,P.E.Understandingthe factors influencing yieldstrengthonMgalloys.ActaMater. 2014,75, 287–296. [CrossRef] 9. Johnston,S.; Shi,Z.;Atrens,A.The influenceofpHonthecorrosionrateofhigh-purityMg,AZ91andZE41 inbicarbonatebufferedHanks’ solution.Corros. Sci. 2015,101, 182–192. [CrossRef] 10. Gupta,M.;Meenashisundaram,G.K. Insight intoDesigningBiocompatibleMagnesiumAlloysandComposites: Processing,Mechanical andCorrosionCharacteristics; Springer:NewYork,NY,USA,2015. 11. Walker, J.; Shadanbaz,S.;Woodfield,T.B.;Staiger,M.P.;Dias,G.J.Magnesiumbiomaterials fororthopedic application: A review fromabiological perspective. J. Biomed. Mater. Res. BAppl. Biomater. 2014, 102, 1316–1331. [CrossRef] [PubMed] 12. Witte,F.Thehistoryofbiodegradablemagnesiumimplants: Areview.ActaBiomater. 2010,6, 1680–1692. [CrossRef] [PubMed] 13. Windhagen, H.; Radtke, K.; Weizbauer, A.; Diekmann, J.; Noll, Y.; Kreimeyer, U.; Schavan, R.; Stukenborg-Colsman,C.;Waizy,H.Biodegradablemagnesium-basedscrewclinicallyequivalent to titanium screwinhalluxvalgussurgery: Short termresultsof thefirstprospective, randomized,controlledclinical pilot study.Biomed. Eng.Online2013,12, 62. [CrossRef] [PubMed] 14. Sietsema,W.Animalmodelsofcorticalporosity.Bone1995,17, S297–S305. [CrossRef] 32