Alamomin ƙwaƙwalwar siffa (SMAs) suna da halayen nakasar martani ga abubuwan motsa jiki na thermomechanical. Thermomechanical stimuli sun samo asali ne daga babban zafin jiki, ƙaura, m-zuwa m canji, da dai sauransu. (high-zazzabi high-oda lokaci ake kira austenite, kuma low-zazzabi low-oda lokaci ake kira martensite). Sauye-sauyen lokaci mai maimaitawa na cyclic yana haifar da karuwa a hankali a cikin raguwa, don haka yankunan da ba a canza su ba za su rage aikin SMA (wanda ake kira gajiya aiki) da kuma samar da microcracks, wanda zai haifar da gazawar jiki lokacin da adadin ya isa. Babu shakka, fahimtar halin gajiyawar rayuwar waɗannan gami, da magance matsalar ɓarkewar ɓangarori masu tsada, da rage haɓakar kayan aiki da sake zagayowar ƙirar samfur, duk za su haifar da matsin tattalin arziki mai girma.
Ba a yi bincike sosai kan gajiyawar zafin jiki ba, musamman rashin bincike kan yaɗuwar gajiya a ƙarƙashin kewayon thermo-mechanical. A farkon aiwatar da SMA a cikin biomedicine, mayar da hankali ga binciken gajiyawa shine jimillar rayuwar samfuran “marasa lahani” ƙarƙashin nauyin injin cyclic. A cikin aikace-aikacen da ke da ƙananan ƙididdiga na SMA, haɓakar gajiyar gajiya ba ta da tasiri a rayuwa, don haka binciken ya mayar da hankali kan hana ƙaddamarwar fashewa maimakon sarrafa girma; a cikin tuki, raguwar girgizawa da aikace-aikacen sha na makamashi, ya zama dole don samun wutar lantarki da sauri. Abubuwan SMA yawanci suna da girma don kula da haɓakar fage kafin gazawar. Don haka, don saduwa da buƙatun amincin da ake buƙata da aminci, ya zama dole don cikakkiyar fahimta da ƙididdige halayen haɓakar gajiya ta hanyar jure lalacewa. Aiwatar da hanyoyin jure lalacewar lalacewa waɗanda suka dogara da ra'ayi na injinan karaya a cikin SMA ba mai sauƙi ba ne. Idan aka kwatanta da karafa na tsarin al'ada, wanzuwar canjin lokaci mai jujjuyawa da haɗin gwiwar injin zafin jiki yana haifar da sabbin ƙalubale don bayyana yadda ya kamata ga gajiya da ɗaukar nauyi na SMA.
Masu bincike daga Jami'ar Texas A&M da ke Amurka sun gudanar da gwaje-gwajen girma na injina mai tsafta da motsa jiki a cikin Ni50.3Ti29.7Hf20 superalloy a karon farko, kuma sun ba da shawarar magana mai ƙarfi irin ta Paris wacce za a iya amfani da ita don Fit the gajiya. ƙwaƙƙwaran girma a ƙarƙashin siga guda ɗaya. An yi la'akari da wannan cewa za a iya daidaita alaƙar haɓakar haɓakar haɓakar haɓaka tsakanin yanayi daban-daban na lodi da kuma daidaitawar lissafi, waɗanda za a iya amfani da su azaman yuwuwar siffanta haɓakar haɓakar ɓarna a cikin SMAs. An buga takardar da ke da alaƙa a cikin Acta Materialia tare da taken "Haɗin kai bayanin injina da gajiyawar gajiyar haɓakar haɓakar sifofin ƙwaƙwalwar ajiya".
Takarda mahada:
doi.org/10.1016/j.actamat.2021.117155
Binciken ya gano cewa lokacin da Ni50.3Ti29.7Hf20 alloy ke fuskantar gwajin tensile uniaxial a 180 ℃, austenite yafi nakasa a ƙarƙashin ƙarancin damuwa yayin aiwatar da lodi, kuma modules ɗin Matasan kusan 90GPa ne. Lokacin da damuwa ya kai game da 300MPa A farkon farkon canji na lokaci mai kyau, austenite ya canza zuwa martensite mai haifar da damuwa; Lokacin saukewa, martensite da ke haifar da damuwa galibi yana fuskantar nakasawa, tare da ma'aunin Matasa na kusan 60 GPa, sannan ya koma austenite. Ta hanyar haɗin kai, ƙimar haɓakar gajiyar haɓakar kayan gini an daidaita su zuwa bayanin dokar ikon nau'in Paris.
Fig.1 Hoton BSE na Ni50.3Ti29.7Hf20 high zafin jiki siffar memory gami da girman rarraba oxide barbashi
Hoto 2 Hoton TEM na Ni50.3Ti29.7Hf20 high zafin jiki siffar ƙwaƙwalwar gami bayan magani mai zafi a 550 ℃ × 3h
Hoto 3 Alakar da ke tsakanin J da da/dN na ci gaban gajiyar inji na NiTiHf DCT a 180 ℃
A cikin gwaje-gwajen da ke cikin wannan labarin, an tabbatar da cewa wannan dabarar za ta iya dacewa da ƙimar girma na gajiya daga duk gwaje-gwajen kuma yana iya amfani da saiti iri ɗaya. Ƙa'idar ikon mai magana m shine kusan 2.2. Binciken karyewar gajiya ya nuna cewa duka yaduwar fasa bututun inji da kuma yaɗuwar fashewar faɗuwar karaya ne, kuma kasancewar hafnium oxide na saman ƙasa akai-akai ya ƙara haɓaka juriya. Sakamakon da aka samu ya nuna cewa furci na ƙa'idar iko guda ɗaya na iya cimma daidaitattun da ake buƙata a cikin yanayi mai yawa na lodawa da daidaitawa na geometric, ta haka ne ke ba da cikakken bayani game da gajiyawar thermomechanical na sifofin ƙwaƙwalwar ajiya, ta haka ne ke kimanta ƙarfin tuki.
Hoton 4 SEM na karyewar samfurin NiTiHf DCT bayan 180 ℃ gwajin girma na gajiya na inji
Hoto 5 Fassara Hoton SEM na samfurin NiTiHf DCT bayan tuki gajiyawar haɓaka haɓakar haɓakar haɓakar ƙima ta 250 N.
A taƙaice, wannan takarda tana gudanar da gwaje-gwajen haɓakar haɓakar ƙira mai tsafta da gajiyarwa akan NiTiHf mai arziƙin nickel mai girman girman sifar ƙwaƙwalwar ajiya a karon farko. Dangane da haɗe-haɗe na keke-da-keke, ana ba da shawarar haɓaka haɓakar doka irin ta Paris don dacewa da ƙimar girmar gajiyar kowane gwaji a ƙarƙashin siga guda ɗaya.
Lokacin aikawa: Satumba-07-2021