Indlela Yokwenziwa Kwayo kunye Neendlela Zokucinezela Iintanda Zokuqina Kwi-Laser Welding

Ukuwelda ngeLaser Beam, ngesantya sayo esiphezulu, ukuchaneka okuphezulu kunye neempawu zokungaqhagamshelani, isetyenziswa kakhulu kwiindawo ezifana neemoto, i-aerospace, kunye nezixhobo ze-elektroniki, ingakumbi ezibonisa iingenelo ezikhethekileyo ekuqhagamshelweni kwezinto ezahlukeneyo. Nangona kunjalo, ii-solidification cracking (Solidification Cracking) eziveliswa ngexesha lenkqubo yokudibanisa zezinye zeziphene eziphambili ezithintela ukusetyenziswa kwayo kwimizi-mveliso. Ezi cracks zihlala zenzeka ekupheleni kokuqina kwindawo yokudibanisa (Fusion Zone), ezibangelwa ziziphumo ezidibeneyo zoxinzelelo lobushushu, ukuncipha kokuqina kunye nefilimu yolwelo kwimida yeenkozo, okunciphisa kakhulu iimpawu zoomatshini kunye nobomi bokudinwa kwejoyinti.

1. Indlela yokwenza izinto

Indlela eyintloko yokuqhekeka kolwelo oluqinileyo ikwifilimu eseleyo yolwelo kwimida yeenkozo ekupheleni kokuqina. Ngexesha lenkqubo yokuqina, ichibi elinyibilikisiweyo lahlulwe laba ziindawo ezintathu: indawo yolwelo olukhululekileyo, indawo yolwelo olulinganiselweyo, kunye nendawo eqinileyo, njengoko kubonisiwe kuMfanekiso 1. Kwindawo yolwelo olulinganiselweyo, ukuhamba kolwelo kuyavalwa kwaye akunakukwazi ukuhlawula uxinzelelo oluveliswa kukuncipha kokuqina, okubangela ukwahlulwa kwemida yeenkozo. Umlinganiselo wamandla omda weenkozo (γgb) kumandla ojongano lwe-solid-liquid (γsl) umisela uzinzo lwefilimu yolwelo: ukuba i-γgb <2γsl, ifilimu yolwelo ayizinzanga kwaye kwenzeka ukuhlangana kweenkozo; ngokuchaseneyo, ifilimu yolwelo izinzile kwaye ukuqaliswa kokuqhekeka kunokwenzeka.

Ngaphezu koko, ukwakheka kweentanda eziqinileyo kukwanxulumene neempawu ze-metallurgical zezinto. Izinto ezahlukeneyo zineempawu ezahlukeneyo zokuqina, ezifana nobubanzi bobushushu bokuqina, izinga lokuncipha kokuqina, kunye nokusasazwa kwezinto ze-alloy, njl. Ezi mpawu zichaphazela uvakalelo lweentanda. Umzekelo, kwizinto eziqulethe inani elikhulu lezigaba ze-eutectic eziphantsi kokunyibilika, uvakalelo lweentanda eziqinileyo luphezulu kuba ezi zigaba ze-eutectic zinokwakheka iifilimu zolwelo eziqhubekayo ngexesha lokuqina, ngaloo ndlela ziqinisa ukwakheka kweentanda.

Ngexeshainkqubo yokuwelda nge-laser, iiparameter zokuwelda ezifana namandla e-laser, isantya sokuwelda, kunye nobukhulu bebala nazo zinempembelelo ekwakhekeni kwee-collision cracks. Ezi parameter zichaphazela ukufakelwa kobushushu kunye ne-gradient yobushushu ngexesha lenkqubo yokuwelda, ngaloo ndlela zitshintsha isakhiwo sokuwelda kunye ne-grain morphology. Umzekelo, amandla aphezulu e-laser kunye nesantya esiphantsi sokuwelda zibangela ukufakelwa kobushushu okukhulu kunye nesantya sokuphola esicothayo, okukhuthaza ukukhula kwee-columnar crystals kwaye kwandisa uvakalelo lokuqhekeka. Ngokwahlukileyo koko, amandla aphantsi e-laser kunye nesantya esiphezulu sokuwelda zikhokelela ekufakweni kobushushu okuncinci kunye nesantya sokuphola ngokukhawuleza, okwenza kube lula ukwenziwa kwee-crystals ezilinganayo kunye nokunciphisa uvakalelo lokuqhekeka.

2. Amanyathelo okunciphisa

Ukuphelisa ngempumelelo iintanda zokuqinaukuwelda nge-laser, abaphandi bacebise amaqhinga ahlukeneyo, agxile kakhulu ekulawuleni isakhiwo sengqolowa, ukuphucula iiparameter zokuwelda, kunye nokuphucula iimpawu zezinto. Ngokucokisa isakhiwo sengqolowa, inani lemida yengqolowa linokwandiswa, kwaye uxinzelelo loxinzelelo lunokuncipha, ngaloo ndlela kuncitshiswe ukwakheka kwemifantu. Izifundo zibonise ukuba ngokusebenzisa itekhnoloji ye-laser beam oscillation, iikristale ze-columnar zinokuguqulwa zibe ziikristale ezintle ze-equiaxed ngaphandle kokongeza ezinye izinto. I-laser beam oscillation inokusasaza amandla e-laser, ibangele ukuba ichibi elinyibilikisiweyo livelise i-turbulence, ngaloo ndlela liphule indlela yokukhula kweekristale ze-columnar kwaye likhuthaze ukwakheka kweekristale ze-equiaxed, njengoko kubonisiwe kuMfanekiso 3. Ukongeza, i-laser beam oscillation inokwandisa ububanzi bechibi elinyibilikisiweyo, inciphise i-gradient yobushushu, kwaye yandise ixesha lokuqina kwechibi elinyibilikisiweyo, elinceda ekusasazekeni kwee-solutes kunye nokuzaliswa kwakhona kweefilimu zolwelo, ngaloo ndlela kunciphisa kakhulu uvakalelo lweemifantu eziqinileyo.

Ukusasazwa kweefilimu zolwelo ezikwimida yeenkozo phantsi kweemilo ezahlukeneyo zedama.

Umzobo weskemakhi wedama elinyibilikisiweyo lokuwelda, a, b) ngaphandle kokujikeleza, c, d) ukujikeleza okusecaleni, e, f) ukujikeleza okude, g, h) ukujikeleza okujikelezayo.

Ukongeza kwiumqadi welaserIteknoloji yokujika, ukusebenzisa imithombo ye-laser ephindwe kabini nayo yenye yeendlela ezisebenzayo zokuthintela iintanda zokuqina. Imithombo ye-laser ephindwe kabini inokufezekisa utshintsho ukusuka kwiikristale ze-columnar ukuya kwiikristale ezilinganayo ngokuphucula umjikelo wobushushu, ngaloo ndlela kunciphisa ubungakanani beenkozo kunye noxinzelelo loxinzelelo. Umzekelo, xa usebenzisa i-CO₂ laser njengomthombo ophambili wobushushu kunye ne-Nd:YAG pulsed laser njengomthombo wobushushu oncedisayo, umjikelo wobushushu ophuculiweyo unokwenziwa ngexesha lokuwelda, ukukhuthaza ukwakheka kweekristale ezilinganayo kunye nokunciphisa uvakalelo lweentanda zokuqina, njengoko kubonisiwe kuMfanekiso 4.

Ukuphucula iiparameter zokuwelda kukwayindlela ebalulekileyo yokuthintela iintanda zokuqina. Ngokulungisa iiparameter ezifana namandla e-laser, isantya sokuwelda, kunye nobukhulu bebala, igalelo lobushushu kunye ne-gradient yobushushu ngexesha lenkqubo yokuwelda zinokulawulwa, ngaloo ndlela zichaphazela isakhiwo sokuqina kunye nemo yengqolowa. Izifundo zibonise ukuba unyango lokufudumeza kwangaphambili lunokunciphisa izinga lokuphola, lukhuthaze ukwakheka kweekristale ezilinganayo, kwaye ngaloo ndlela lunciphise uvakalelo lweentanda zokuqina, njengoko kubonisiwe kuMfanekiso 5. Ukongeza, iindlela ezinje ngokusebenzisa i-pulsed laser welding kunye nokwandisa isantya sokuwelda nazo zinokufezekisa utshintsho ukusuka kwiikristale zekholamu ukuya kwiikristale ezilinganayo ngokutshintsha igalelo lobushushu kunye nezinga lokuphola, ngaloo ndlela zinciphisa uvakalelo lweentanda.

Umfanekiso 5. a) Ayifudunyezwanga, b) Iinkozo ezilinganisiweyo ezishushu ngama-300°C.

Xa kudityaniswa izinto ezingafaniyo ngeelaser, ngenxa yomahluko omkhulu kwiimpawu zomzimba nezekhemikhali phakathi kwezinto, iikhompawundi ze-brittle intermetallic ziyathanda ukwakheka, ezizezinye zezizathu eziphambili zokuqhekeka kokuqina. Ke ngoko, ukulungisa iiparameter zelaser kunye noseto ukunciphisa ukwakheka okanye ubungakanani beekhompawundi ze-intermetallic kukwayindlela ebalulekileyo yokuthintela ukuqhekeka kokuqina. Umzekelo, ekudibaniseni ngelaser kwezinto ezingafaniyo ze-copper-aluminium, ngokulawula ukungalingani kwe-laser beam kunye nesantya sokuqhekeka, umlinganiselo wokuxuba ubhedu kunye ne-aluminium kwidama elinyibilikisiweyo unokuncipha, ngaloo ndlela kunciphisa ukwakheka kweekhompawundi ze-brittle intermetallic kunye nokunciphisa uvakalelo lwee-cracks. Ukongeza, ukusebenzisa izinto zokuzalisa kunokuphucula ukusebenza kwejoyinti edibeneyo kunye nokunciphisa ukwakheka kwee-cracks. Izinto zokuzalisa zinokunciphisa ukwakheka kweekhompawundi ze-intermetallic ngokutshintsha ukwakheka kunye nesakhiwo sejoyinti edibeneyo kunye nokuphucula ukuqina kwejoyinti edibeneyo.

Iimfantu eziqina ziphakathi kweziphene eziqhelekileyo kwiinkqubo zokuwelda nge-laser. Indlela yazo yokwenza iyinkimbinkimbi kwaye ibandakanya ukusebenzisana kwezinto ezininzi ezifana nobushushu, i-mechanics, kunye ne-metallurgy. Ngokufunda nzulu indlela yokwenza iimfantu eziqina ngayo, isiseko sethiyori sinokubonelelwa ngokucinezela iimfantu. Kwiminyaka yakutshanje, abaphandi bacebise amaqhinga ahlukeneyo okuthintela iimfantu eziqina, ezigxila kakhulu ekulawuleni isakhiwo sengqolowa, ukuphucula iiparameter zokuwelda, kunye nokuphucula iimpawu zezinto. Ukuziqhelanisa kuye kwabonisa ukuba la maqhinga anokunciphisa ngempumelelo uvakalelo lweemfantu eziqina ukuya kwinqanaba elithile kwaye aphucule umgangatho kunye nokuthembeka kwe-laser welding. Nangona kunjalo, ngenxa yobunzima kunye nokwahluka kwenkqubo yokuwelda nge-laser, kusekho iziphene ezithile kuphando lwangoku. Umzekelo, kwiinkqubo zokuthintela iimfantu eziqina phantsi kwezixhobo ezahlukeneyo kunye neemeko zokuwelda, kusafuneka uphando olunzulu ngakumbi.