Ultrafine-Grained Austenitic Stainless Steels X4CrNi18-12 and X8CrMnNi19-6-3 Produ Accu"ulati#e $oll %ondin& Mat'is $u((ert )* +isa Patricia ,reund * 'o"as .en/l * 0ein/ .erner 0 ((el and Ma e(art"ent of Materials Science and n&ineerin&* 5nstitute 5 General Materials P ,riedric'-Ale7ander Uni#ersit t rlan&en-N rner&* Martensstr: ;* 91<;8 rlan&en Mails lisa:freund>fau:de ?+:P:,:@= t'o"as: en/l>fau:de ? :.:@= ' e:'oe((el>fau:d "at'ias:&oe en> :uni-erlan&en:de ?M:G:@ ) Aut'or to 'o" corres(ondence s'ould e addressed= -Mail "at'is:ru((ert>fau:de= 9131-8;2 4 8= ,a7 B49-9131-8;2 ;<4: Acade"ic ditor 0u&o ,: +o(e/ $ecei#ed 3< Marc' 2<1; D Acce(ted 4 Ma! 2<1; D Pulis'ed Ma! 2<1; Abstract : Austenitic stainless steels X4CrNi18-12 and X8CrMnNi19-6-3 ere (rocessed ! acc roll ondin& ?A$%@: %ot' "aterials s'o an e7tre"el! 'i&' !ield stren&t' of 1:2; G acco"(anied ! a satisfactor! elon&ation to failure of u( to 14E and a (ositi#e st sensiti#it! after t o A$% c!cles: 'e strain-'ardenin& rate of t'e austenitic stee staili/ation of t'e stress-strain e'a#ior durin& tensile testin&: s(eciall! fo 'ic' 'as an ele#ated "an&anese content of 6: t:E* nec in& is (re#ented u( to c 'i&' (lastic strains: Microstructural in#esti&ations s'o ed t'at t'e "icrostructur ultrafine-&rained c'annel li e areas and relati#el! lar&er &rains 'ere (ronounce and "artensite for"ation is oser#ed: Fe! ords accu"ulati#e roll ondin& ?A$%@= austenitic steel= ultrafine-&rained "icrostructur t innin&= strain rate sensiti#it! 1. Introduction Accu"ulati#e roll ondin& ?A$%@ 1H as a (rocess of se#ere (lastic defor"ation is effecti#e "et'ods for t'e (roduction of ul ultrafine-&rained ?U,G@ "aterials i si/e s"aller t'an 1 I": 'e "icrostructural e#olution durin& A$% is ell descried see for e7a"(le 2*3*4H for details: 'e "ec'anical (ro(erties of t'ose "aterials clai"ed to e fa#orale co"(ared to t'eir con#entionall! &rained ?CG@ counter(arts co"ination of 'i&' stren&t' and satisfactor! ductilit! can e ac'ie#ed ;*6*H: ductilit! is often rou&'t into connection it' t'e en'anced strain rate sensiti#i "aterials: Moreo#er* strain rate sensiti#it! is stron&l! related to an increased f oundaries 4H* as t'e! can act as sources and sin s for dislocations 3H: Alt'ou nu"erous (ulications on A$% a#ailale* onl! a cou(le of t'e" are dealin& it' A$% of steel-s'eets: A"on& t'ose* t'e "aKorit! concerns interstitial free cc steels ? rat'er lo content of allo!in& ele"ents* see for e7a"(le 1*1<*11*12H: 0o e#er* t' literature a#ailale aout A$% of austenitic steels* 'ic' ill e focused on in t Fita'ara et al: 13H in#esti&ated t'e "artensite transfor"ation of an ultrafine-&r ENi-allo! it' sin&le ('ase "etastale austenite at roo" te"(erature: 'e! (erfor" accu"ulati#e roll ondin& (rocess it' s'eets t'at ere (re-'eated at ;<< LC for 6 c!cles: 0o e#er* eac' c!cle as di#ided into t o (asses it' a t'ic ness reductio ac'ie#ed an ultrafine-&rained "icrostructure it' a "ean &rain si/e of 23< n" and t'at as increased ! a factor of 4:9 co"(ared to t'e initial "aterial: Moreo#er* t'e "artensite transfor"ation startin& te"(erature decreases it' t'e nu"er of A$ Anot'er stud! aout A$% of austenitic steel as (ulis'ed ! afarian et al: 14H: