Shape memory alloys (SMAs) ane hunhu deformation mhinduro kune thermomechanical stimuli. Thermomechanical stimuli inobva pakupisa kwepamusoro, kutama, kusimba-kusvika-yakasimba shanduko, nezvimwewo (yakakwirira-yakakwirira-yakakwirira-yakarongeka chikamu chinonzi austenite, uye yakadzika-yakadzika-yakadzika-yakarongeka chikamu chinonzi martensite). Kudzokororwa kwe cyclic phase transitions kunotungamirira kukuwedzera zvishoma nezvishoma mukuparadzaniswa, saka nzvimbo dzisina kuchinjwa dzichaderedza kushanda kweSMA (inonzi kushanda kuneta) uye inogadzira microcracks, iyo inozopedzisira yaita kuti kukundikana kwemuviri kana nhamba yakakura zvakakwana. Zviripachena, kunzwisisa mafambiro ehupenyu hwekuneta kweaya alloys, kugadzirisa dambudziko rekudhura kwechinhu chakaraswa, uye kudzikisira kusimukira kwezvinhu uye kutenderera kwekugadzirwa kwechigadzirwa zvese zvinounza dzvinyiriro huru yehupfumi.
Thermo-mechanical kuneta haina kuongororwa kusvika pamwero mukuru, kunyanya kushaikwa kwekutsvagisa pamusoro pekuneta kutsemuka kupararira pasi pe thermo-mechanical cycles. Mukutanga kuitiswa kweSMA mubiomedicine, chinangwa chekutsvaga kwekuneta hwaive hupenyu hwese hwe "hurema-husina" samples pasi pe cyclic mechanical mitoro. Mumaapplication ane diki SMA geometry, kuneta crack kukura kune zvishoma pahupenyu, saka tsvakiridzo inotarisisa kudzivirira kutanga kwe crack pane kudzora kukura kwayo; mukutyaira, kuderedza vibration uye kushandiswa kwesimba kunyura, zvinodikanwa kuti uwane simba nekukurumidza. Zvikamu zveSMA zvinowanzokura zvakakwana kuti zvichengetedze kupararira kwakakura kusati kwatadza. Naizvozvo, kuti usangane nekuvimbika kunodiwa uye chengetedzo zvinodiwa, zvinodikanwa kuti unzwisise zvizere uye kuverengera kuneta crack growth maitiro kuburikidza nekukuvara kushivirira nzira. Iko kushandiswa kwekukuvara kushivirira nzira dzinotsamira pane iyo pfungwa yekuputsika mechanics muSMA haisi nyore. Zvichienzaniswa nesimbi dzechinyakare, kuvepo kweinodzoreredzwa chikamu shanduko uye thermo-mechanical coupling zvinounza matambudziko matsva kutsanangura zvinobudirira kuneta uye kuwandisa kutsemuka kweSMA.
Vatsvagiri kubva kuTexas A&M University kuUnited States vakaita hunyanzvi hwekuita uye kuneta kwakakura kuyedza muNi50.3Ti29.7Hf20 superalloy kekutanga, uye vakakurudzira-inoenderana-yakavakirwa Paris-mhando yesimba mutemo kutaura iyo inogona kushandiswa Fit kuneta. kuputika mwero wekukura pasi peparameter imwe chete. Zvinofungidzirwa kubva pane izvi kuti hukama hwe empirical ne crack growth rate inogona kuiswa pakati pemamiriro akasiyana ekurodha uye geometric configurations, iyo inogona kushandiswa sechinhu chinogoneka chakabatana descriptor ye deformation crack growth muSMAs. Iro bepa rine hukama rakaburitswa muActa Materialia ine zita rekuti "Tsananguro yakabatana yemakanika uye actuation kuneta kuputika muchimiro chendangariro alloys".
Pepa link:
https://doi.org/10.1016/j.actamat.2021.117155
Chidzidzo ichi chakawana kuti kana Ni50.3Ti29.7Hf20 alloy ikaitwa uniaxial tensile bvunzo pa180 ℃, iyo austenite inonyanya kuremara pasi peyakaderera stress level panguva yekurodha, uye Yechidiki modulus inenge 90GPa. Kana kushushikana kunosvika pa300MPa Pakutanga kweiyo yakanaka chikamu shanduko, austenite inoshandura kuita kusagadzikana-induced martensite; pakuburutsa, stress-induced martensite inonyanya kuita elastic deformation, iine Young's modulus inosvika 60 GPa, yobva yachinja kudzokera ku austenite. Kuburikidza nekubatanidzwa, kuneta kwekukura kwekukura kwezvimiro zvakagadzirirwa kuParis-mhando yemutemo mutemo kutaura.
Fig.1 BSE mufananidzo weNi50.3Ti29.7Hf20 yakakwira tembiricha chimiro chendangariro alloy uye saizi kugovera kwe oxide zvimedu
Mufananidzo 2 TEM mufananidzo weNi50.3Ti29.7Hf20 yakakwira tembiricha chimiro chendangariro alloy mushure mekupisa kurapwa pa550℃×3h.
Fig. 3 Hukama huripo pakati peJ ne da/dN ye mechanical fatigue crack growth yeNiTiHf DCT specimen pa 180℃
Muzviyedzo zviri muchinyorwa chino, zvinoratidzwa kuti fomula iyi inogona kuenderana nekuneta kwekukura kwe data kubva kune zvese zviedzo uye inogona kushandisa imwechete seti yemaparamita. Iyo simba mutemo exponent m inenge 2.2. Kufenda kutyoka kwekuongorora kunoratidza kuti ese ari maviri mechanical crack propagation uye kutyaira kutsemuka kuri quasi-cleavage fractures, uye kugara kuvapo kwepamusoro hafnium oxide kwakawedzera kuramba kupararira kwekuputika. Mhedzisiro yakawanikwa inoratidza kuti imwe empirical simba mutemo kutaura inogona kuwana kufanana kunodiwa munzvimbo dzakasiyana-siyana dzekurodha uye geometric masisitimu, nekudaro ichipa yakabatana tsananguro ye thermo-mechanical kuneta kwechimiro memory alloys, nokudaro kufungidzira simba rekutyaira.
Fig. 4 SEM mufananidzo wekutyoka kweNiTiHf DCT muenzaniso mushure me180℃ mechanical fatigue crack growth experiment.
Mufananidzo 5 Kuputsika SEM mufananidzo weNiTiHf DCT sampuli mushure mekutyaira kuneta crack kukura kuyedza pasi pekugara kwakarerekera kwe250 N.
Muchidimbu, bepa iri rinoitisa kwakachena mechanic uye kutyaira kuneta crack growth kuyedza pane nickel-rich NiTiHf yakakwirira tembiricha chimiro memory alloys kekutanga. Zvichienderana nekubatanidzwa kwe cyclic, yeParis-mhando yesimba-mutemo crack kukura kutaura inokurudzirwa kuti ikwane kuneta kwekukura kwekukura kweyeyedzero yega yega pasi peparamita imwe chete.
Nguva yekutumira: Sep-07-2021