![\"Youngov](\"https:\/\/aluminaceramics.net\/wp-content\/uploads\/2024\/06\/Youngs-Modulus-of-Alumina.jpg\")
<\/p>","protected":false},"excerpt":{"rendered":"Youngov modul je neocenite\u013en\u00fdm meradlom pre nede\u0161trukt\u00edvne testovanie \u017eiaruvzdorn\u00fdch materi\u00e1lov a sl\u00fa\u017ei ako indik\u00e1tor mikro\u0161trukt\u00farneho in\u017einierstva t\u00fdchto \u017eiaruvzdorn\u00fdch materi\u00e1lov.<\/p>\n
Na \u0161t\u00fadium tern\u00e1rneho syst\u00e9mu zlo\u017een\u00e9ho z oxidu hlinit\u00e9ho-ZrO2-YAG sa pou\u017eila skenovacia transmisn\u00e1 elektr\u00f3nov\u00e1 mikroskopia (STEM). Podrobne sme charakterizovali najm\u00e4 druh\u00fa f\u00e1zu nach\u00e1dzaj\u00facu sa pozd\u013a\u017e hran\u00edc zrn oxidu hlinit\u00e9ho a medzi jednotliv\u00fdmi zrnami pomocou SEM zobrazenia.<\/p>\n
In\u017einieri vyu\u017e\u00edvaj\u00fa Youngov modul na pos\u00fadenie toho, ak\u00e9 nam\u00e1hanie m\u00f4\u017ee materi\u00e1l vydr\u017ea\u0165, k\u00fdm sa trvalo nedeformuje alebo nezlyh\u00e1, \u010do im pom\u00e1ha vytv\u00e1ra\u0165 kon\u0161trukcie, ktor\u00e9 odol\u00e1vaj\u00fa vonkaj\u0161\u00edm sil\u00e1m bez toho, aby praskali alebo sa rozpadali. V\u00fdpo\u010det Youngovho modulu si vy\u017eaduje presn\u00e9 merania, znalos\u0165 mechaniky pru\u017enosti a presn\u00fd sp\u00f4sob predpovedania reakcie materi\u00e1lov pri nam\u00e1han\u00ed.<\/p>\n
Sk\u00fa\u0161ka \u0165ahom je z\u00e1kladn\u00fdm sp\u00f4sobom merania Youngovho modulu. Vzorka materi\u00e1lu je vystaven\u00e1 postupne sa zvy\u0161uj\u00facemu \u0165ahov\u00e9mu nam\u00e1haniu, a\u017e k\u00fdm sa nedosiahne jeho hranica pru\u017enosti; merania sily a deform\u00e1cie v ka\u017edom bode tohto procesu sa potom zaznamenaj\u00fa pred vykreslen\u00edm na krivku nap\u00e4tie-deform\u00e1cia so sklonom pru\u017enej oblasti, ktor\u00e1 predstavuje Youngov modul materi\u00e1lu.<\/p>\n
Youngov modul sa d\u00e1 mera\u0165 aj r\u00f4znymi in\u00fdmi sp\u00f4sobmi. Jednou z tak\u00fdchto techn\u00edk je nanoindent\u00e1cia, ktor\u00e1 sa \u010dasto pou\u017e\u00edva na charakteriz\u00e1ciu mechanick\u00fdch vlastnost\u00ed v mikro- a nanorozmeroch; tak\u00e9to testy si v\u0161ak vy\u017eaduj\u00fa testovacie zariadenia s vysok\u00fdm rozl\u00ed\u0161en\u00edm, ako aj \u0161pecifick\u00e9 n\u00e1stroje na pr\u00edpravu vzoriek na anal\u00fdzu.<\/p>\n
Jednou z v\u00fdhod pou\u017e\u00edvania nanoindent\u00e1ci\u00ed na meranie Youngovho modulu s\u00fa men\u0161ie po\u017eiadavky na vzorky ako pri tradi\u010dn\u00fdch \u0165ahov\u00fdch sk\u00fa\u0161kach, v\u010faka \u010domu sa z\u00edskavaj\u00fa rozdelenia s pravidelnej\u0161\u00edmi krivkami rozdelenia, ktor\u00e9 umo\u017e\u0148uj\u00fa presnej\u0161ie \u0161tatistick\u00e9 korekcie, ako je to mo\u017en\u00e9 pri rozdeleniach v plnom rozsahu.<\/p>\n
Youngov modul pre hlin\u00edk bol dobre stanoven\u00fd na z\u00e1klade experiment\u00e1lnych meran\u00ed a teoretick\u00fdch v\u00fdpo\u010dtov a t\u00e1to hodnota sa m\u00f4\u017ee pou\u017ei\u0165 ako porovn\u00e1vac\u00ed bod pri v\u00fdpo\u010dtoch alebo experiment\u00e1lnych meraniach. Zmeny v Youngovom module m\u00f4\u017eu by\u0165 sp\u00f4soben\u00e9 faktormi, ako je teplota, zlo\u017eenie zliatiny, kry\u0161t\u00e1lov\u00e1 \u0161trukt\u00fara alebo v\u00fdrobn\u00e9 procesy - napr\u00edklad pridanie leguj\u00facich prvkov m\u00f4\u017ee zmeni\u0165 usporiadanie medzimolekul\u00e1rnych v\u00e4zieb, a t\u00fdm aj jeho mechanick\u00e9 vlastnosti.<\/p>\n
Poissonov pomer je vlastnos\u0165 materi\u00e1lu, ktor\u00e1 meria vz\u0165ah medzi pozd\u013a\u017enou a prie\u010dnou deform\u00e1ciou. Jeho hodnota sa men\u00ed v z\u00e1vislosti od typu deform\u00e1cie; pri deform\u00e1cii v \u0165ahu je kladn\u00e1, zatia\u013e \u010do pri deform\u00e1cii v tlaku m\u00f4\u017ee by\u0165 z\u00e1porn\u00e1. Hoci hodnoty Poissonovho pomeru maj\u00fa tendenciu zost\u00e1va\u0165 v r\u00f4znych materi\u00e1loch rovnak\u00e9, ich hodnoty sa m\u00f4\u017eu medzi materi\u00e1lmi v\u00fdrazne meni\u0165; tento jav je obzvl\u00e1\u0161\u0165 v\u00fdrazn\u00fd pri kovoch a zliatin\u00e1ch, ktor\u00e9 \u010dasto vykazuj\u00fa ve\u013ek\u00e9 rozdiely v hodnot\u00e1ch Poissonovho pomeru.<\/p>\n
Poissonov pomer sa zvy\u010dajne zni\u017euje so zvy\u0161uj\u00facou sa hustotou v d\u00f4sledku zmien v bunkov\u00fdch \u0161trukt\u00farach materi\u00e1lu, ktor\u00e9 menia tvar a ve\u013ekos\u0165 p\u00f3rov, \u010do ovplyv\u0148uje Poissonov pomer. Okrem toho zhus\u0165ovanie men\u00ed rozlo\u017eenie p\u00f3rov, ako aj rozlo\u017eenie ich ve\u013ekosti; zhus\u0165ovanie ovplyv\u0148uje aj tento proces. Mnoh\u00e9 \u0161t\u00fadie sk\u00famali tento vz\u0165ah pomocou r\u00f4znych vibra\u010dn\u00fdch met\u00f3d, ako je meranie rezonan\u010dn\u00fdch frekvenci\u00ed s vysokou presnos\u0165ou - presn\u00e9 meranie, ktor\u00e9 umo\u017e\u0148uje v\u00fdpo\u010dty elastick\u00fdch vlastnost\u00ed vzoriek.<\/p>\n
Tieto v\u00fdpo\u010dty mo\u017eno vykona\u0165 pomocou nede\u0161trukt\u00edvnej techniky naz\u00fdvanej ultrazvukov\u00e9 meranie. Ide o poklepanie na vzorku projektilom a zaznamenanie jeho vibra\u010dn\u00e9ho sign\u00e1lu na anal\u00fdzu, aby sa zistili r\u00fdchlosti pozd\u013a\u017enych a prie\u010dnych akustick\u00fdch v\u013an; potom sa tieto inform\u00e1cie pou\u017eij\u00fa na v\u00fdpo\u010det Youngovho modulu materi\u00e1lu vzorky na z\u00e1klade tejto met\u00f3dy anal\u00fdzy - v\u017edy sa tak z\u00edskaj\u00fa konzistentn\u00e9 a presn\u00e9 v\u00fdsledky.<\/p>\n
Youngov modul pre oxid hlinit\u00fd mo\u017eno vysvetli\u0165 pomocou jeho hustoty a Poissonovho pomeru, dvoch hlavn\u00fdch prvkov jeho pru\u017en\u00e9ho spr\u00e1vania. Hlin\u00edk m\u00e1 n\u00edzky Poissonov pomer v d\u00f4sledku svojej mikro\u0161trukt\u00fary; v d\u00f4sledku toho sa jeho elastick\u00e9 vlastnosti zvy\u0161uj\u00fa s rast\u00facou hustotou; jeho Youngov modul v\u0161ak zost\u00e1va ni\u017e\u0161\u00ed ako u porovnate\u013en\u00fdch kovov.<\/p>\n
Poissonov pomer v oxidu hlinitom je citliv\u00fd na jeho teplotu. Zatia\u013e \u010do s rast\u00facou teplotou kles\u00e1, po dosiahnut\u00ed teploty v\u00fdpalu prudko st\u00fapa sp\u00e4\u0165 v d\u00f4sledku pokra\u010duj\u00faceho spekania pri tejto teplote, \u010do vedie k n\u00e1hlemu zv\u00fd\u0161eniu Youngovho modulu. Bohu\u017eia\u013e, jeho presn\u00fd vz\u0165ah k zmen\u00e1m teploty zost\u00e1va nedostato\u010dne pochopen\u00fd v d\u00f4sledku r\u00f4znych vplyvov, ktor\u00e9 ho ovplyv\u0148uj\u00fa.<\/p>\n
Modul pru\u017enosti je integr\u00e1lnou vlastnos\u0165ou pevn\u00fdch materi\u00e1lov. Opisuje, k akej deform\u00e1cii doch\u00e1dza pri \u0165ahu alebo tlaku, pri\u010dom tuh\u00e9 materi\u00e1ly maj\u00fa vy\u0161\u0161ie moduly pru\u017enosti ako pru\u017en\u00e9; zn\u00e1me aj ako modul pru\u017enosti v \u0165ahu\/\u0165ahu alebo modul pru\u017enosti pri deform\u00e1cii, meranie modulu pru\u017enosti sa m\u00f4\u017ee uskuto\u010dni\u0165 meran\u00edm nap\u00e4tia sp\u00f4soben\u00e9ho deform\u00e1ciou pri kon\u0161tantnom za\u0165a\u017een\u00ed a n\u00e1sledn\u00fdm vydelen\u00edm deform\u00e1ciou, \u010d\u00edm sa z\u00edska jeho hodnota - \u010d\u00edm sa z\u00edska hodnota modulu pru\u017enosti.<\/p>\n
Tuhos\u0165, opak modulu pru\u017enosti, meria, ak\u00e1 ve\u013ek\u00e1 sila p\u00f4sob\u00ed pri nam\u00e1han\u00ed. In\u017einieri pou\u017e\u00edvaj\u00fa t\u00fato vlastnos\u0165 materi\u00e1lov na ur\u010denie ich \u00fanosnosti a vykonanie potrebn\u00fdch \u00faprav; jej hodnota m\u00f4\u017ee z\u00e1visie\u0165 od faktorov, ako je hr\u00fabka a vlastnosti materi\u00e1lu.<\/p>\n
Hrub\u0161ie hlin\u00edkov\u00e9 dosky bud\u00fa ma\u0165 ni\u017e\u0161iu tuhos\u0165, ale rovnak\u00e9 hodnoty Youngovho modulu, preto\u017ee hrub\u0161ie materi\u00e1ly s\u00fa odolnej\u0161ie vo\u010di deform\u00e1cii pri nam\u00e1han\u00ed a maj\u00fa v\u00e4\u010d\u0161ie plochy, tak\u017ee na vyvolanie deform\u00e1cie v danom bode je potrebn\u00e9 pou\u017ei\u0165 v\u00e4\u010d\u0161ie nap\u00e4tie.<\/p>\n
Moduly pru\u017enosti mo\u017eno porovna\u0165 pomocou nasleduj\u00facej rovnice: E (T) = b(ph(T)) 6(k B T), kde ph-g predstavuje funkciu pr\u00e1ce elektr\u00f3nov pri T a b je hustota materi\u00e1lu.<\/p>\n
Oxid hlinit\u00fd je keramika odoln\u00e1 vo\u010di oderu s vysok\u00fdm modulom pru\u017enosti, ktor\u00fd mo\u017eno charakterizova\u0165 trojbodov\u00fdmi a \u0161tvorbodov\u00fdmi sk\u00fa\u0161kami ohybu. V tejto \u0161t\u00fadii sa pou\u017eila numericko-experiment\u00e1lna korel\u00e1cia na predpovedanie vlastn\u00e9ho Youngovho modulu povlaku oxidu hlinit\u00e9ho nanesen\u00e9ho na hlin\u00edkov\u00fd substr\u00e1t a zistila sa vynikaj\u00faca zhoda medzi jeho experiment\u00e1lnymi a predpovedan\u00fdmi hodnotami. Okrem toho sa uk\u00e1zalo, \u017ee tlakov\u00e9 nam\u00e1hanie je silnej\u0161ie ako \u0165ahov\u00e9 nam\u00e1hanie pri v\u00e4\u010d\u0161ine aplik\u00e1ci\u00ed vyu\u017e\u00edvaj\u00facich povlaky oxidu hlinit\u00e9ho; \u010do nazna\u010duje \u00faspe\u0161nej\u0161ie fungovanie.<\/p>\n
Vysok\u00fd Youngov modul oxidu hlinit\u00e9ho ho ozna\u010duje za tuh\u00fd materi\u00e1l odoln\u00fd vo\u010di deform\u00e1cii, zatia\u013e \u010do jeho neplastickos\u0165 a nedostatok medze klzu ho rob\u00ed nevhodn\u00fdm pre aplik\u00e1cie, ktor\u00e9 vy\u017eaduj\u00fa plasticitu, ako s\u00fa kon\u0161truk\u010dn\u00e9 komponenty a rezn\u00e9 n\u00e1stroje. Namiesto toho doch\u00e1dza k jeho zlyhaniu pri tlakovom alebo \u0165ahovom za\u0165a\u017een\u00ed takmer okam\u017eite, namiesto toho, aby sa postupne deformoval a \u010dasom oslaboval. Vzh\u013eadom na t\u00fato vlastnos\u0165 je jeho krehk\u00fd charakter nevhodn\u00fd na tak\u00e9 pou\u017eitie, ako s\u00fa kon\u0161truk\u010dn\u00e9 komponenty alebo rezn\u00e9 n\u00e1stroje, ktor\u00e9 vy\u017eaduj\u00fa plasticitu.<\/p>\n
Hlin\u00edk mo\u017eno kombinova\u0165 s polym\u00e9rmi, aby sa v\u00fdrazne zv\u00fd\u0161ili ich \u0165ahov\u00e9 vlastnosti. Napr\u00edklad pridan\u00edm 0,2% nanovl\u00e1kien oxidu hlinit\u00e9ho do epoxidov\u00e9ho kompozitu sa zv\u00fd\u0161i jeho pevnos\u0165 v \u0165ahu zo 41 MPa na 71 MPa, preto\u017ee nanovl\u00e1kna oxidu hlinit\u00e9ho prid\u00e1vaj\u00fa tuhos\u0165 a p\u00f4sobia ako prirodzen\u00e9 obmedzova\u010de re\u0165azca, ako aj sa sp\u00e1jaj\u00fa s epoxidov\u00fdmi skupinami v re\u0165azcoch polym\u00e9rov prostredn\u00edctvom svojich epoxypropylov\u00fdch funk\u010dn\u00fdch skup\u00edn, ktor\u00e9 vytv\u00e1raj\u00fa pevn\u00e9 v\u00e4zby medzi vl\u00e1knami a molekulami \u017eivice.<\/p>\n
\u0160es\u0165uholn\u00edkov\u00fd oxid hlinit\u00fd je ide\u00e1lnym technick\u00fdm keramick\u00fdm materi\u00e1lom v\u010faka svojmu vysok\u00e9mu Youngovmu modulu a n\u00edzkej tepelnej roz\u0165a\u017enosti, v\u010faka \u010domu je odoln\u00fd vo\u010di mechanick\u00e9mu nam\u00e1haniu pri vysok\u00fdch teplot\u00e1ch. Okrem toho hexagon\u00e1lny oxid hlinit\u00fd pon\u00faka vynikaj\u00facu vodivos\u0165, ako aj stabiln\u00fd v\u00fdkon v extr\u00e9mnych podmienkach prostredia - vlastnosti, v\u010faka ktor\u00fdm je hexagon\u00e1lny oxid hlinit\u00fd vynikaj\u00facou vo\u013ebou pre elektrotechnick\u00e9 aplik\u00e1cie.<\/p>\n
Na rozdiel od in\u00fdch typov oxidu hlinit\u00e9ho m\u00e1 hexagon\u00e1lny AlN extr\u00e9mne vysok\u00fd koeficient samodif\u00fazie, ktor\u00fd s\u0165a\u017euje spekanie tradi\u010dn\u00fdmi met\u00f3dami. Okrem toho sa tento materi\u00e1l m\u00f4\u017ee pochv\u00e1li\u0165 n\u00edzkou teplotou tavenia a vynikaj\u00facimi vlastnos\u0165ami odolnosti vo\u010di tepeln\u00fdm \u0161okom.<\/p>\n
Testovanie sonelastick\u00fdch syst\u00e9mov pri izbovej teplote, ako aj pri n\u00edzkych a vysok\u00fdch teplot\u00e1ch umo\u017e\u0148uje presn\u00fa charakteriz\u00e1ciu modulov pru\u017enosti (Youngov modul, \u0161mykov\u00fd modul a Poissonov pomer) a tlmiacich vlastnost\u00ed keramick\u00fdch materi\u00e1lov s cie\u013eom presne pos\u00fadi\u0165 ich moduly pru\u017enosti (Youngov modul, \u0161mykov\u00fd modul a Poissonov pomer) a tlmiace charakteristiky - tieto vlastnosti s\u00fa nevyhnutn\u00e9 pri navrhovan\u00ed nov\u00fdch variantov t\u00fdchto materi\u00e1lov pre \u0161irok\u00e9 spektrum aplik\u00e1ci\u00ed.<\/p>\n
Po\u010das procesu spekania sa dynamicky merali moduly pru\u017enosti oxidu hlinit\u00e9ho. Pri ni\u017e\u0161\u00edch teplot\u00e1ch sa Youngov modul line\u00e1rne zni\u017eoval v d\u00f4sledku \u010diasto\u010dn\u00e9ho zhutnenia spekan\u00e9ho oxidu hlinit\u00e9ho; pri vy\u0161\u0161\u00edch teplot\u00e1ch v\u0161ak v d\u00f4sledku \u010fal\u0161ieho zhut\u0148ovania Youngov modul r\u00fdchlo r\u00e1stol v d\u00f4sledku procesov spekania a zhut\u0148ovania; tento trend bol v s\u00falade so statick\u00fdmi meraniami toho ist\u00e9ho materi\u00e1lu pri izbovej teplote; podobn\u00e9 trendy vykazovali aj \u0161mykov\u00fd modul a Poissonov pomer.<\/p>\n
<\/p>","protected":false},"excerpt":{"rendered":"
Young’s modulus is an invaluable measure for nondestructive testing of refractory materials and serves as an indicator of microstructure engineering […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[6],"tags":[],"class_list":["post-100","post","type-post","status-publish","format-standard","hentry","category-alumina-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/posts\/100","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/comments?post=100"}],"version-history":[{"count":3,"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/posts\/100\/revisions"}],"predecessor-version":[{"id":195,"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/posts\/100\/revisions\/195"}],"wp:attachment":[{"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/media?parent=100"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/categories?post=100"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aluminaceramics.net\/sk\/wp-json\/wp\/v2\/tags?post=100"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}