I-CoCrFeNi yi-cubic (fcc) ye-high-entropy alloy (HEA) ene-ductility egqwesileyo kodwa amandla alinganiselweyo. Ingqwalasela yolu phononongo kukuphucula ibhalansi yamandla kunye ne-ductility ye-HEAs ngokongeza amanani ahlukeneyo e-SiC usebenzisa indlela yokunyibilika kwe-arc. Kuye kwasekwa ukuba ubukho bechromium kwisiseko se-HEA bubangela ukubola kwe-SiC ngexesha lokunyibilika. Ngaloo ndlela, ukusebenzisana kwekhabhoni yamahhala kunye ne-chromium kukhokelela ekubunjweni kwe-situ ye-chromium carbides, ngelixa i-silicon yamahhala ihlala kwisisombululo kwisiseko se-HEA kunye / okanye idibanisa kunye nezinto ezenza isiseko se-HEA ukwenza i-silicides. Njengoko umxholo we-SiC ukhula, isigaba se-microstructure sitshintsha ngokulandelelana okulandelayo: fcc → fcc + eutectic → fcc + chromium carbide flakes → fcc + chromium carbide flakes + silicide → fcc + chromium carbide flakes + silicide + graphite balls / graphite flakes. Imixube enesiphumo ibonisa uluhlu olubanzi kakhulu lweempawu zoomatshini (amandla esivuno asuka kwi-277 MPa ngaphezulu kobude obungama-60% ukuya kuma-2522 MPa kubude obuyi-6%) xa kuthelekiswa neealloyi eziqhelekileyo kunye ne-entropy alloys ephezulu. Ezinye zeentropy eziphezulu eziphuhlisiwe zibonisa indibaniselwano egqwesileyo yeempawu zoomatshini (amandla esivuno angama-1200 MPa, ulwandiso lwama-37%) kwaye athatha imimandla ebikade ingenakufikelelwa kwidayagram yokwandisa uxinzelelo lwesivuno. Ukongeza kubude obumangalisayo, ubulukhuni kunye nokomelela kwesivuno se-HEA edityanisiweyo kukuluhlu olufanayo neeglasi zentsimbi ezininzi. Ke ngoko, kukholelwa ukuba uphuhliso lwee-composites eziphezulu ze-entropy lunokunceda ukufezekisa indibaniselwano egqwesileyo yeepropathi zoomatshini kusetyenziso oluphezulu lwesakhiwo.
Ukuphuhliswa kwee-alloys eziphezulu ze-entropy yingcamango entsha ethembisayo kwi-metallurgy1,2. I-alloys ephezulu ye-entropy (HEA) ibonise kwiimeko ezininzi indibaniselwano egqwesileyo yeempawu zomzimba kunye noomatshini, kubandakanywa ukuzinza okuphezulu kwe-thermal3,4 i-superplastic elongation5,6 ukuxhathisa ukukhathala7,8 ukumelana nokugqwala9,10,11, ukuxhathisa okugqwesileyo12,13,14 ,15 kunye neempawu zetribological15 ,16,17 nakubushushu obuphezulu18,19,20,21,22 kunye noomatshini iipropati kumaqondo obushushu aphantsi23,24,25. Indibaniselwano egqwesileyo yeepropathi zoomatshini kwi-HEA zihlala zibalelwa kwiziphumo ezine eziphambili, ezizezi, uqwalaselo oluphezulu lwe-entropy26, i-lattice distortion27 eyomeleleyo, i-diffusion ecothayo28 kunye ne-cocktail effect29. Ii-HEA zidla ngokuhlelwa njengeFCC, BCC kunye neentlobo ze-HCP. I-FCC HEA iqulethe izinto eziguqukayo ezifana ne-Co, i-Cr, i-Fe, i-Ni kunye ne-Mn kwaye ibonisa i-ductility egqwesileyo (kwanakwiqondo lokushisa eliphantsi25) kodwa amandla aphantsi. I-BCC HEA idla ngokuqulunqwa ngezinto ezixineneyo eziphezulu ezifana ne-W, Mo, Nb, Ta, Ti kunye ne-V kwaye inamandla aphezulu kakhulu kodwa i-ductility ephantsi kunye namandla athile aphantsi30.
Ukuguqulwa kwe-microstructural ye-HEA esekelwe kumatshini, ukulungiswa kwe-thermomechanical kunye nokongezwa kwezinto kuye kwaphandwa ukuze kufumaneke indibaniselwano engcono kakhulu yeempawu zomatshini. I-CoCrFeMnNi i-FCC HEA ixhomekeke kwi-deformation enzima yeplastiki nge-high-pressure torsion, ekhokelela ekunyuseni okukhulu kobunzima (520 HV) kunye namandla (1950 MPa), kodwa ukuphuhliswa kwe-nanocrystalline microstructure (~ 50 nm) yenza i-alloy brittle31 . Kufunyaniswe ukuba ukudityaniswa kwe-twinning ductility (TWIP) kunye ne-plasticity induced (TRIP) kwi-CoCrFeMnNi HEAs inika umsebenzi olungileyo ukuqina okukhokelela kubunzima obuphezulu be-tensile ductility, nangona indleko yokwenyani amandla okuqina. Ngezantsi (1124 MPa) 32. Ukubunjwa kwe-microstructure elayishiweyo (ebandakanya umaleko obhityileyo okhubazekileyo kunye nombindi ongaguqukiyo) kwi-CoCrFeMnNi HEA usebenzisa i-shot peening kubangele ukwanda kwamandla, kodwa olu phuculo lwalulinganiselwe malunga ne-700 MPa33. Ukukhangela izinto eziphathekayo ezinokubambisana okuhle kakhulu kwamandla kunye ne-ductility, ukuphuhliswa kwe-HEAs ye-multiphase kunye ne-eutectic HEAs usebenzisa izongezo zezinto ezingezona i-isoatomic nazo ziye zaphandwa34,35,36,37,38,39,40,41. Enyanisweni, kuye kwafunyaniswa ukuba ukusabalalisa okucokisekileyo kwezigaba ezinzima kunye nezithambileyo kwi-eutectic high-entropy alloys kunokukhokelela ekudibaneni okungcono kwamandla kunye ne-ductility35,38,42,43.
Inkqubo ye-CoCrFeNi yi-alloy ye-FCC ephezulu-entropy efundwa ngokubanzi. Le nkqubo ibonisa iipropathi ezikhawulezayo zokuqina komsebenzi44 kunye ne-ductility egqwesileyo45,46 kumaqondo obushushu aphantsi naphezulu. Iinzame ezahlukeneyo zenziwe ukuphucula amandla alo aphantsi kakhulu (~ 300 MPa)47,48 kubandakanywa ukucoca okuziinkozo25, i-heterogeneous microstructure49, i-precipitation50,51,52 kunye ne-plasticity-induced plasticity (TRIP)53. Ukucocwa kweenkozo zecubic ye-HEA CoCrFeNi egxininiswe kubuso ngobuso ngomzobo obandayo phantsi kweemeko ezinzima kwandisa amandla ukusuka malunga ne-300 MPa47.48 ukuya kwi-1.2 GPa25, kodwa kunciphisa ilahleko ye-ductility ukusuka ngaphezulu kwe-60% ukuya kwi-12.6%. Ukongezwa kwe-Al kwi-HEA ye-CoCrFeNi kubangele ukusekwa kwe-microstructure ene-heterogeneous, eyandisa amandla ayo esivuno ukuya kwi-786 MPa kunye nobude bayo obuhambelanayo malunga ne-22% ye-49. I-CoCrFeNi HEA yongezwa kunye ne-Ti kunye ne-Al ukwenza imvula, ngaloo ndlela yenze ukuqina kwemvula, inyusa amandla ayo esivuno ukuya kuma-645 MPa kunye nokwandisa ukuya kuma-39%51. Indlela ye-TRIP (i-cubic egxile ebusweni → i-hexahedral martensitic transformation) kunye ne-twinning yonyuse amandla okuqina e-CoCrFeNi HEA ukuya kuma-841 MPa kunye nobude bekhefu ukuya kuma-76%53.
Iinzame zenziwe kwakhona ukongeza i-ceramic yokuqinisa kwi-HEA ubuso obugxile kwi-cubic matrix ukuphuhlisa imidibaniso ephezulu ye-entropy enokubonisa indibaniselwano engcono yamandla kunye ne-ductility. Ii-composites ezine-entropy ephezulu ziqhutywe yi-vacuum arc melting44, i-alloying yomatshini45,46,47,48,52,53, i-spark plasma sintering46,51,52, i-vacuum eshushu icinezela45, i-isostatic eshushu icinezela47,48 kunye nophuhliso lweenkqubo zokwenziwa kwe-additive43. 50. I-Carbides, i-oxides kunye ne-nitrides ezifana ne-WC44, i-45, i-46, i-Al2O347, i-SiC48, i-TiC43, i-49, i-TiN50 kunye ne-Y2O351 isetyenziswe njengokuqiniswa kwe-ceramic kuphuhliso lwe-HEA composites. Ukukhetha i-matrix ye-HEA efanelekileyo kunye ne-ceramic ibaluleke kakhulu xa uyilwa kwaye uphuhlisa i-HEA eyomeleleyo kunye neyomelele. Kulo msebenzi, iCoCrFeNi yakhethwa njengesixhobo sematrix. Izixa ezahlukeneyo ze-SiC zongezwa kwi-CoCrFeNi HEA kunye nefuthe labo kwi-microstructure, ukubunjwa kwesigaba, kunye neempawu zomatshini zafundwa.
Iintsimbi ezicocekileyo eziphezulu ze-Co, i-Cr, i-Fe, kunye ne-Ni (99.95 wt%) kunye ne-SiC powder (ukuhlambuluka kwe-99%, ubukhulu -400 mesh) ngendlela yeengqungquthela ezisisiseko zisetyenziswe njengezinto ezibonakalayo ekudalweni kwee-composites ze-HEA. Ukubunjwa kwe-isoatomic ye-CoCrFeNi HEA yaqala ukufakwa kwi-hemispherical water-cooled copper mold, kwaye ke igumbi likhutshwe kwi-3 · 10-5 mbar. Ukucoceka okuphezulu kwegesi ye-argon kwaziswa ukuphumeza i-vacuum efunekayo yokunyibilika kwe-arc kunye ne-electrode ye-tungsten engasetyenziswayo. Ii-ingots ezibangelwayo ziguqulwa kwaye zihlanjululwe kahlanu ukuze kuqinisekiswe i-homogeneity elungileyo. I-High-entropy composite ye-composites eyahluka-hlukeneyo yalungiselelwa ngokudibanisa inani elithile le-SiC kwii-coCrFeNi ze-equiatomic ezibangelwa amaqhosha, aphinde ahlaziywa nge-homogenized nge-five-fold inversion kunye ne-remelting kwimeko nganye. Iqhosha elibunjiweyo elivela kwi-composite elibangelwayo lisikwe kusetyenziswa i-EDM yokuvavanya ngakumbi kunye nokulinganisa. Iisampulu zezifundo ze-microstructural zalungiswa ngokweendlela eziqhelekileyo ze-metallographic. Okokuqala, iisampuli zavavanywa kusetyenziswa i-microscope yokukhanya (i-Leica Microscope DM6M) kunye ne-software ye-Leica Image Analysis (I-LAS Phase Expert) yohlalutyo lwesigaba sobungakanani. Imifanekiso emithathu ethatyathwe kwiindawo ezahlukeneyo ezinommandla omalunga ne-27,000 µm2 yakhethwa ukuze kuhlalutywe isigaba. Uphononongo oluthe kratya oluneenkcukacha lwe-microstructural, kubandakanywa uhlalutyo lokwakheka kweekhemikhali kunye nohlalutyo lokusasazwa kwezinto, lwenziwa kwi-electronic microscope yokuskena (JEOL JSM-6490LA) exhotyiswe ngenkqubo yohlalutyo ye-energy dispersive spectroscopy (EDS). Ukubonakaliswa kwesakhiwo se-crystal ye-HEA composite senziwa ngokusebenzisa inkqubo ye-X-ray diffraction (i-Bruker D2 phase shifter) usebenzisa umthombo we-CuKα kunye nobukhulu besinyathelo se-0.04 °. Umphumo wotshintsho lwe-microstructural kwiipropati ze-mechanical ze-HEA composite zafundwa kusetyenziswa iimvavanyo ze-Vickers microhardness kunye neemvavanyo zoxinzelelo. Kuvavanyo lobunzima, umthwalo we-500 N usetyenziselwa i-15 s usebenzisa ubuncinane i-10 indentations kwi-specimen nganye. Uvavanyo loxinzelelo lwee-HEA ze-composites kwiqondo lokushisa kwegumbi lwenziwa kwiimpawu ezixande (7 mm × 3 mm × 3 mm) kumatshini wokuvavanya ummandla we-Shimadzu 50KN (UTM) kwinqanaba lokuqala loxinzelelo lwe-0.001 / s.
Iicomposites eziphezulu ze-entropy, emva koko zibizwa ngokuba ziisampuli ze-S-1 ukuya kwi-S-6, zalungiswa ngokudibanisa i-3%, i-6%, i-9%, i-12%, i-15%, kunye ne-17% ye-SiC (konke ngobunzima%) kwi-matrix ye-CoCrFeNi. . ngokulandelelanayo. Isampulu yesalathiso apho kungekho SiC yongezwayo emva koku kubhekiselwa kuyo njengesampulu S-0. I-Micrographs ye-Optical ye-HEA ephuhlisiwe edibeneyo iboniswe kwiMifanekiso. I-1, apho, ngenxa yokongezwa kwezongezo ezahlukeneyo, i-microstructure yesigaba esisodwa se-CoCrFeNi HEA yatshintshwa ibe yi-microstructure equkethe izigaba ezininzi ezine-morphology, ubukhulu kunye nokusabalalisa. Isixa se-SiC ekuqulunqweni. Isixa sesigaba ngasinye sinqunywe kuhlalutyo lwemifanekiso kusetyenziswa isoftware yeNgcali yeSigaba se-LAS. I-inset kwi-Figure 1 (phezulu ekunene) ibonisa ummandla womzekelo wolu hlalutyo, kunye neqhezu lendawo yecandelo lesigaba ngasinye.
Iimicrographs zamehlo eziphuhlisiwe ezine-high-entropy composite: (a) C-1, (b) C-2, (c) C-3, (d) C-4, (e) C-5 kunye (f) C- 6. I-inset ibonisa umzekelo weziphumo zohlalutyo lwesigaba somfanekiso ochaseneyo usebenzisa i-software yeNgcali yeSigaba se-LAS.
Njengoko kubonisiwe kwifig. I-1a, i-eutectic microstructure eyenziwe phakathi kwemithamo ye-matrix ye-C-1 edibeneyo, apho isixa se-matrix kunye nezigaba ze-eutectic ziqikelelwa njenge-87.9 ± 0.47% kunye ne-12.1% ± 0.51%, ngokulandelanayo. Kwi-composite (C-2) eboniswe kwi-Fig. 1b, akukho zibonakaliso ze-eutectic reaction ngexesha lokuqina, kwaye i-microstructure ehluke ngokupheleleyo kwi-C-1 edibeneyo ibonwa. I-microstructure ye-C-2 edibeneyo ilungile kwaye iqulethe iipleyiti ezincinci (i-carbides) ezisasazwa ngokufanayo kwisigaba se-matrix (fcc). Iinqununu zevolumu ye-matrix kunye ne-carbide ziqikelelwa kwi-72 ± 1.69% kunye ne-28 ± 1.69%, ngokulandelanayo. Ukongeza kwi-matrix kunye ne-carbide, isigaba esitsha (i-silicide) sifunyenwe kwi-C-3 composite, njengoko kuboniswe kwi-Fig. 0.41%, 25.9 ± 0.53, kunye ne-47.6 ± 0.34, ngokulandelanayo. Esinye isigaba esitsha (igraphite) siphinde sabonwa kwi-microstructure ye-C-4 composite; zizonke izigaba ezine zachongwa. Isigaba segraphite sinomfanekiso weglowubhu owahlukileyo kunye nokwahlukana okumnyama kwimifanekiso ye-optical kwaye ikhona kuphela kwiimali ezincinci (i-fraction ye-volume eqikelelweyo imalunga ne-0.6 ± 0.30%). Kwii-composites ze-C-5 kunye ne-C-6, kuphela izigaba ezintathu ezichongiweyo, kwaye isigaba esimnyama esahlukileyo segraphite kule ngqungquthela sibonakala ngendlela yeeflakes. Xa kuthelekiswa ne-graphite flakes kwi-Composite S-5, i-graphite flakes kwi-Composite S-6 ibanzi, imfutshane, kwaye ihlala rhoqo. Ukunyuka okuhambelanayo kumxholo wegraphite kuye kwabonwa ukusuka kwi-14.9 ± 0.85% kwi-C-5 edibeneyo ukuya malunga ne-17.4 ± 0.55% kwi-C-6 edibeneyo.
Ukuphanda ngakumbi ubume be-microstructure kunye nokwakhiwa kweekhemikhali zesigaba ngasinye kwi-HEA composite, iisampulu zavavanywa kusetyenziswa i-SEM, kunye nohlalutyo lwamanqaku e-EMF kunye nemephu yeekhemikhali nazo zenziwa. Iziphumo ze-composite C-1 ziboniswe kwifig. 2, apho ubukho bemixube ye-eutectic eyahlula imimandla yesigaba esiphambili se-matrix ibonakala ngokucacileyo. Imephu yemichiza ye-C-1 edibeneyo iboniswe kwi-Fig. 2c, apho kunokubonwa ukuba i-Co, i-Fe, i-Ni, kunye ne-Si ihanjiswa ngokufanayo kwisigaba se-matrix. Nangona kunjalo, inani elincinci le-Cr lifunyenwe kwisigaba se-matrix xa kuthelekiswa nezinye izinto zesiseko se-HEA, ebonisa ukuba i-Cr yasasazeka ngaphandle kwe-matrix. Ukubunjwa kwesigaba esimhlophe se-eutectic kumfanekiso we-SEM sisityebi kwi-chromium kunye nekhabhoni, ebonisa ukuba yi-chromium carbide. Ukungabikho kweengqungquthela ze-SiC kwi-microstructure, edibeneyo kunye nomxholo ophantsi obonwayo we-chromium kwi-matrix kunye nobukho bemixube ye-eutectic equkethe izigaba ezicebileyo ze-chromium, ibonisa ukubola okupheleleyo kwe-SiC ngexesha lokunyibilika. Njengomphumo wokubola kwe-SiC, i-silicon inyibilika kwisigaba se-matrix, kwaye i-carbon yamahhala idibanisa ne-chromium ukwenza i-chromium carbides. Njengoko kunokubonwa, i-carbon kuphela yayinqunywe ngokomgangatho ngendlela ye-EMF, kwaye ukubunjwa kwesigaba kwaqinisekiswa ngokuchongwa kweempawu ze-carbide eziphakamileyo kwiipatheni ze-X-ray diffraction.
(a) umfanekiso we-SEM wesampulu S-1, (b) umfanekiso owandisiweyo, (c) imephu yesiqalelo, (d) iziphumo ze-EMF kwiindawo ezibonisiweyo.
Uhlalutyo lwe-composite C-2 luboniswe kumzobo. 3. Ngokufana nokubonakala kwi-microscopy ye-optical, uviwo lwe-SEM lubonakalise isakhiwo esihle esakhiwe ngamanqanaba amabini kuphela, kunye nobukho besigaba esincinci se-lamellar esisasazwa ngokulinganayo kulo lonke isakhiwo. isigaba se-matrix, kwaye akukho sigaba se-eutectic. Ukuhanjiswa kwezinto kunye nohlalutyo lwamanqaku e-EMF kwisigaba se-lamellar kubonise umxholo ophezulu kakhulu we-Cr (ophuzi) kunye no-C (oluhlaza) kwesi sigaba, esiphinda sibonise ukubola kwe-SiC ngexesha lokunyibilika kunye nokusebenzisana kwekhabhoni ekhutshiweyo kunye nefuthe le-chromium. . I-VEA matrix yenza isigaba se-lamellar carbide. Ukuhanjiswa kwezinto kunye nohlalutyo lwamanqaku esigaba se-matrix kubonise ukuba ininzi ye-cobalt, isinyithi, i-nickel kunye ne-silicon zikhona kwisigaba se-matrix.
(a) umfanekiso we-SEM wesampulu S-2, (b) umfanekiso owandisiweyo, (c) imephu yesiqalelo, (d) iziphumo ze-EMF kwiindawo ezibonisiweyo.
Izifundo ze-SEM ze-C-3 ezidibeneyo zibonise ubukho bezigaba ezitsha ngaphezu kwezigaba ze-carbide kunye ne-matrix. Imephu esisiseko (umzobo 4c) kunye nohlalutyo lwamanqaku e-EMF (umzobo 4d) lubonisa ukuba isigaba esitsha sisityebi kwi-nickel, i-cobalt kunye ne-silicon.
(a) umfanekiso we-SEM wesampulu S-3, (b) umfanekiso owandisiweyo, (c) imephu yesiqalelo, (d) iziphumo ze-EMF kwiindawo ezibonisiweyo.
Iziphumo ze-SEM kunye nohlalutyo lwe-EMF ye-C-4 edibeneyo iboniswe kwiMifanekiso. 5. Ukongeza kwizigaba ezithathu ezibonwe kwi-composite C-3, ubukho be-graphite nodules bufunyenwe. Inxalenye yomthamo wesigaba esityebileyo se-silicon nayo iphezulu kuneyo ye-C-3 edibeneyo.
(a) umfanekiso we-SEM wesampulu S-4, (b) umfanekiso owandisiweyo, (c) imephu yesiqalelo, (d) iziphumo ze-EMF kwiindawo ezibonisiweyo.
Iziphumo ze-SEM kunye ne-EMF ye-spectra ye-composites S-5 kunye ne-S-6 iboniswe kwiMifanekiso 1 kunye ne-2. 6 kunye ne-7, ngokulandelanayo. Ukongeza kwinani elincinci leengqungquthela, ubukho be-graphite flakes nabo babonwa. Zombini inani lee-graphite flakes kunye neqhezu lomthamo wesigaba se-silicon equlethwe kwi-C-6 composite inkulu kune-C-5 composite.
(a) Umfanekiso we-SEM wesampulu C-5, (b) umbono owandisiweyo, (c) imephu ye-elemental, (d) iziphumo ze-EMF kwiindawo ezibonisiweyo.
(a) umfanekiso we-SEM wesampulu S-6, (b) umfanekiso owandisiweyo, (c) imephu yesiqalelo, (d) iziphumo ze-EMF kwiindawo ezibonisiweyo.
Ubume bekristale besimo sezinto ezihlanganisiweyo ze-HEA nazo zenziwa kusetyenziswa imilinganiselo ye-XRD. Isiphumo siboniswe kuMfanekiso 8. Kwipatheni ye-diffraction yesiseko se-WEA (S-0), kuphela iinqununu ezihambelana nesigaba se-fcc ziyabonakala. Iipateni ze-X-ray diffraction ze-composites C-1, C-2, kunye ne-C-3 zibonise ubukho beencopho ezongezelelweyo ezihambelana ne-chromium carbide (Cr7C3), kwaye ukuqina kwazo kwakungaphantsi kwiisampuli ze-C-3 kunye ne-C-4, ezibonisa ukuba kwakhona kunye nedatha ye-EMF yezi sampuli. Iincopho ezihambelana ne-Co / Ni silicides zabonwa kwiisampuli ze-S-3 kunye ne-S-4, ziphinde zihambelane neziphumo zemephu ye-EDS eboniswe kwiMifanekiso 2 kunye ne-3. Njengoko kuboniswe kuMfanekiso 3 kunye noMfanekiso 4. I-5 kunye ne-S-6 iincopho zabonwa. ehambelana negraphite.
Zombini iimpawu ze-microstructural kunye ne-crystallographic ze-composites eziphuhlisiwe zibonise ukubola kwe-SiC eyongezelelweyo. Oku kungenxa yobukho bechromium kwi-VEA matrix. I-Chromium inobudlelwane obuqinileyo kakhulu bekhabhoni ye-54.55 kwaye isabela ngekhabhoni yasimahla ukwenza i-carbides, njengoko kubonisiwe ngokuncipha okuphawulweyo kumxholo we-chromium we-matrix. U-Si udlula kwisigaba se-fcc ngenxa yokuqhawulwa kwe-SiC56. Ngaloo ndlela, ukwanda kokongezwa kwe-SiC kwisiseko se-HEA kwakhokelela ekwandeni kwenani lesigaba se-carbide kunye nenani le-Si yamahhala kwi-microstructure. Kufunyenwe ukuba le Si eyongezelelweyo ifakwe kwi-matrix kwiindawo eziphantsi (kwii-composites S-1 kunye ne-S-2), ngelixa kwiindawo eziphezulu (i-composites S-3 ukuya kwi-S-6) iphumela kwi-cobalt eyongezelelweyo yokubeka /. nickel silicide. I-enthalpy esemgangathweni yokwakheka kwe-Co kunye ne-Ni silicides, efunyenwe ngokuthe ngqo kwi-calorimetry ephezulu yobushushu bokushisa, yi -37.9 ± 2.0, -49.3 ± 1.3, -34.9 ± 1.1 kJ mol -1 ye-Co2Si, i-CoSi kunye ne-CoSi2, ngokulandelanayo, ngelixa ezi amaxabiso are - 50.6 ± 1.7 kunye - 45.1 ± 1.4 kJ mol-157 ye-Ni2Si kunye ne-Ni5Si2, ngokulandelanayo. Ezi xabiso ziphantsi kunobushushu bokwenziwa kwe-SiC, ebonisa ukuba ukuchithwa kwe-SiC okukhokelela ekuyilweni kwe-Co/Ni silicides kuyathandeka ngamandla. Kuzo zombini i-S-5 kunye ne-S-6 edibeneyo, i-silicon eyongezelelweyo yamahhala yayikhona, eyayixutywe ngaphaya kokubunjwa kwe-silicide. Le silicon yamahhala ifunyenwe igalelo kwi-graphitization ebonwe kwiintsimbi eziqhelekileyo58.
Iipropati zomatshini we-ceramic-reinforced composites eziphuhlisiwe ezisekelwe kwi-HEA ziphandwa ngovavanyo loxinzelelo kunye neemvavanyo zokuqina. I-stress-strain curves ye-composites ephuhlisiwe iboniswe kwiMifanekiso. I-9a, kunye ne-Fig. 9b ibonisa i-scatterplot phakathi kwamandla athile okuvelisa, amandla okuvelisa, ukuqina, kunye nokwandiswa kwee-composites eziphuhlisiweyo.
(a) Iigophe ezicinezelayo kunye (b) ne-scatterplots ebonisa uxinzelelo oluthile lwesivuno, amandla esivuno, ukuqina kunye nobude. Qaphela ukuba kuboniswa kuphela iisampulu S-0 ukuya kwi-S-4, njengoko imizekelo ye-S-5 kunye ne-S-6 iqulethe iziphene ezibalulekileyo zokuphosa.
Njengoko kubonwa kwifig. I-9, amandla okuvelisa anyuke ukusuka kwi-136 MPa kwisiseko seVES (C-0) ukuya kwi-2522 MPa ye-C-4 edibeneyo. Xa kuthelekiswa nesiseko seWPP, i-S-2 ehlanganisiweyo ibonise ulwabelo oluhle kakhulu lokungaphumeleli malunga ne-37%, kwaye yabonisa amaxabiso amandla esivuno aphezulu (1200 MPa). Ukudibanisa okugqwesileyo kwamandla kunye ne-ductility yale ngqungquthela kubangelwa ukuphuculwa kwe-microstructure jikelele, kubandakanywa nokusabalalisa okufanayo kwe-carbide lamellae ecocekileyo kuyo yonke i-microstructure, ekulindeleke ukuba inqanda ukunyakaza kwe-dislocation. Amandla esivuno se-C-3 kunye ne-C-4 ehlanganisiweyo yi-1925 MPa kunye ne-2522 MPa, ngokulandelanayo. Ezi zivuno eziphezulu zokuvunwa ziyakwazi ukuchazwa ngumthamo ophezulu we-carbide ene-cemented kunye nezigaba ze-silicide. Nangona kunjalo, ubukho bezi zigaba bukwakhokelele ekwandiseni ixesha lekhefu nge-7% kuphela. Uxinzelelo lwe-stress-strain curves of the base composites CoCrFeNi HEA (S-0) kunye ne-S-1 i-convex, ebonisa ukusebenza kwempembelelo ye-twinning okanye i-TRIP59,60. Xa kuthelekiswa nesampulu ye-S-1, i-curve ye-stress-strain yesampuli ye-S-2 ine-concave shape kwi-strain emalunga ne-10.20%, oku kuthetha ukuba isiliphu esiqhelekileyo sokuchithwa kweyona ndlela iphambili ye-deformation yesampulu kule meko ekhubazekileyo60,61 . Nangona kunjalo, izinga lokuqina kulo mzekelo lihlala liphezulu kuluhlu olukhulu loxinzelelo, kwaye kwiintlobo eziphakamileyo inguqu kwi-convexity nayo ibonakala (nangona ingenakukhutshwa ukuba oku kungenxa yokusilela kwemithwalo yoxinzelelo olufakwe i-lubricated). ). I-Composites i-C-3 kunye ne-C-4 ine-plasticity elinganiselweyo kuphela ngenxa yobukho be-volume fractions ephezulu ye-carbides kunye ne-silicides kwi-microstructure. Iimvavanyo zoxinzelelo lweesampulu ze-composites ze-C-5 kunye ne-C-6 azizange zenzeke ngenxa yeziphene ezibalulekileyo zokuphosa kwezi sampuli ze-composites (jonga i-Fig. 10).
I-Stereomicrographs yeziphene zokuphosa (eziboniswe ngeentolo ezibomvu) kwiisampuli ze-composites C-5 kunye ne-C-6.
Iziphumo zokulinganisa ubulukhuni be-VEA composites ziboniswa kwiFig. 9b. Isiseko WEA unobulukhuni 130±5 HV, kunye neesampulu S-1, S-2, S-3 kunye S-4 amaxabiso ubulukhuni 250±10 HV, 275±10 HV, 570±20 HV kunye 755±20 HV. Ukunyuka kobunzima kwakuvumelana kakuhle kunye nokuguqulwa kwamandla esivuno afunyenwe kwiimvavanyo zokuxinzelela kwaye kwahlanganiswa nokunyuka kwenani lezinto eziqinileyo kwi-composite. Amandla esivuno esithile esibalwe ngokusekwe ekubunjweni okujoliswe kuko kwesampulu nganye kukwaboniswa kwifig. 9b. Ngokubanzi, ukudibanisa okugqwesileyo kwamandla esivuno (1200 MPa), ubunzima (275 ± 10 HV), kunye nobude obusondeleyo bokungaphumeleli (~ 37%) bujongwa kwi-composite C-2.
Uthelekiso lwamandla esivuno kunye nokwandiswa okuzalanayo komdibaniso ophuhlisiweyo kunye nemathiriyeli yeeklasi ezahlukeneyo kuboniswe kuMzobo 11a. Ii-Composites ezisekwe kwi-CoCrFeNi kolu phononongo zibonise ubude obuphezulu kulo naliphi na inqanaba loxinzelelo olunikiweyo62. Kwakhona kunokubonwa ukuba iipropati zemixube ye-HEA ephuhliswe kolu phononongo zikwindawo ebikade ingasetyenziswanga yeploti yamandla esivuno xa kuthelekiswa nobude. Ukongeza, ii-composites eziphuhlisiweyo zineendlela ezininzi zokudibanisa amandla (277 MPa, 1200 MPa, 1925 MPa kunye ne-2522 MPa) kunye nobude (> 60%, 37%, 7.3% kunye ne-6.19%). Amandla esivuno sikwayinto ebalulekileyo ekukhetheni izixhobo zezicelo zobunjineli obuphambili63,64. Ngokuphathelene noku, imidibaniso ye-HEA yoyilo lwangoku lubonisa indibaniselwano ebalaseleyo yamandla esivuno kunye nobude. Oku kungenxa yokuba ukongezwa koxinaniso oluphantsi lwe-SiC lukhokelela kwiintlanganisela ezinamandla athile aphezulu esivuno. Amandla athile esivuno kunye nokwandiswa kwee-composites ze-HEA kuluhlu olufanayo ne-HEA FCC kunye ne-REfractory HEA, njengoko kubonisiwe kwi-Fig. 11b. Ukuqina kunye nokomelela kwesivuno semidibaniso ephuhlisiweyo ikuluhlu olufanayo neeglasi ezinkulu zentsimbi65 (Umfanekiso 11c). Iiglasi ezinkulu zentsimbi (BMS) ziphawulwa ngobulukhuni obuphezulu kunye nokomelela kwesivuno, kodwa ubude bazo bulinganiselwe ngama-66,67. Nangona kunjalo, ukuqina kunye namandla emveliso yezinye ze-HEA ezihlanganisiweyo eziphuhliswe kolu phononongo nazo zibonise ubude obubalulekileyo. Ngaloo ndlela, kwagqitywa ukuba i-composites ephuhliswe yi-VEA inodibaniso olulodwa kunye nokufunwa emva kweepropathi zomatshini ukwenzela izicelo ezahlukeneyo zesakhiwo. Olu dibaniso olukhethekileyo lweempawu zomatshini lunokuchazwa ngokusasazwa okufanayo kweekhabhide ezinzima ezenziwe kwindawo kwi-matrix yeFCC HEA. Nangona kunjalo, njengenxalenye yenjongo yokufezekisa indibaniselwano engcono yamandla, utshintsho lwe-microstructural olubangelwa ukongezwa kwezigaba ze-ceramic kufuneka zifundwe ngokucophelela kwaye zilawulwe ukuze zigweme ukuphosa iziphene, ezifana nezo zifumaneka kwii-composites ze-S-5 kunye ne-S-6, kwaye i-ductility. isini.
Iziphumo zolu phononongo zifaniswa nezixhobo ezahlukeneyo zesakhiwo kunye ne-HEAs: (a) ubude kunye nokuqina kwesivuno62, (b) uxinzelelo oluthile lwesivuno ngokuchasene ne-ductility63 kunye (c) nokuqina kwesivuno ngokuchasene nobunzima65.
Ubume be-microstructure kunye neepropathi zomatshini zoluhlu lwe-HEA-ceramic composites esekwe kwinkqubo ye-HEA CoCrFeNi kunye nokongezwa kwe-SiC ziye zafundwa kwaye ezi zigqibo zilandelayo zenziwe:
Iimbumba eziphezulu ze-entropy alloy zingaphuhliswa ngempumelelo ngokudibanisa i-SiC kwi-CoCrFeNi HEA usebenzisa indlela yokunyibilika kwe-arc.
I-SiC ibola ngexesha lokunyibilika kwe-arc, ekhokelela ekubunjweni kwi-situ ye-carbide, i-silicide kunye nezigaba zegraphite, ubukho kunye neqhezu levolumu elixhomekeke kwinani le-SiC elongezelelweyo kwi-HEA yesiseko.
Imidibaniso ye-HEA ibonisa iipropati ezininzi ezigqwesileyo zoomatshini, ezineepropati eziwela kwiindawo ebezingahlali mntu ngaphambili kumandla esivuno xa kuthelekiswa neploti yobude. Amandla esivuno se-HEA edibeneyo eyenziwe kusetyenziswa i-6 wt% SiC yayingaphezu kwamaxesha asibhozo e-HEA esisiseko ngelixa igcina i-37% ductility.
Ukuqina kunye nokomelela kwesivuno se-HEA composites kuluhlu lweeglasi zentsimbi ezininzi (BMG).
Iziphumo zicebisa ukuba i-high-entropy alloy composites imele indlela ethembisayo yokuphumeza indibaniselwano egqwesileyo yeepropathi zentsimbi zoomatshini kusetyenziso oluphezulu lwesakhiwo.
Ixesha lokuposa: Jul-12-2023