Itemu ye-hard alloy(1)

Ukuthuthukisa ukuqonda kwemibiko nemibhalo yobuchwepheshe emayelana ne-hard alloy, ukwenza amagama afane, futhi achaze incazelo yamagama obuchwepheshe kuma-athikili, silapha ukuze sifunde imigomo ye-hard alloy.

I-Tungsten Carbide

I-Tungsten carbide isho izinhlanganisela ze-sintered ezihlanganisa i-refractory metal carbides nezibophezelo zensimbi. Phakathi kwama-carbides ensimbi asetshenziswayo njengamanje, i-tungsten carbide (WC), i-titanium carbide (TiC), ne-tantalum carbide (TaC) yizingxenye ezivame kakhulu. Insimbi ye-cobalt isetshenziswa kabanzi ekukhiqizeni i-carbide enosimende njenge-binder. Kwezinye izinhlelo zokusebenza ezikhethekile, izibophezelo zensimbi ezifana ne-nickel (Ni) ne-iron (Fe) nazo zingasetshenziswa.

Ukuminyana

Ukuminyana kubhekisela esilinganisweni sesisindo somthamo wevolumu, esibizwa nangokuthi amandla adonsela phansi athile. Umthamo wayo uqukethe nomthamo wama-pores kundaba. I-Tungsten carbide (WC) inokuminyana okungu-15.7 g/cm³ futhi i-cobalt (Co) inokuminyana okungu-8.9 g/cm³. Ngakho-ke, njengoba okuqukethwe kwe-cobalt (Co) ku-tungsten-cobalt alloys (WC-Co) kuncipha, ukuminyana kuzokwanda. Nakuba ukuminyana kwe-titanium carbide (TiC) kungaphansi kwaleyo ye-tungsten carbide, kungu-4.9 g/cm3 kuphela. Uma i-TiC noma ezinye izingxenye eziminyene kancane zengezwa, ukuminyana kuzo zonke kuzokwehla. Ngokwakhiwa kwamakhemikhali okuthile kwezinto, ukwanda kwama-pores kumphumela wokunciphisa ukuminyana.

Ukuqina

Ubulukhuni busho ikhono lempahla ukumelana nokuguquguquka kwepulasitiki.

I-Vickers hardness (HV) isetshenziswa kabanzi emhlabeni jikelele. Le ndlela yokulinganisa ubulukhuni ibhekisela enanini lokuqina elitholwe ngokusebenzisa idayimane ukuze kungene indawo engaphezulu yesampula ukuze kukale usayizi wokuhlehlisa ngaphansi kwesimo esithile somthwalo. Ukuqina kwe-Rockwell (HRA) kungenye indlela yokulinganisa ubulukhuni evame ukusetshenziswa. Isebenzisa ukujula kokungena kwekhoni yedayimane evamile ukukala ubulukhuni. Kokubili ubulukhuni be-Vickers kanye nobulukhuni be-Rockwell kungasetshenziswa ukulinganisa ubulukhuni be-carbide esimende, futhi okubili kungaguqulelwa komunye nomunye.

Amandla okugoba

Amandla okugoba aziwa nangokuthi amandla okuphuka aguquguqukayo noma amandla aguqukayo. Ama-alloys aqinile angeziwe njengensimbi yokusekela elula kuma-pivots amabili, bese umthwalo usetshenziswa ku-centerline yazo zombili ama-pivots kuze kube yilapho i-alloy eqinile iqhuma. Amanani abalwe kusukela kufomula ejikajikayo asetshenziselwa umthwalo odingekayo ukuze uphuke, kanye nendawo ehlukanisayo yesampula. Kuma-alloys e-tungsten-cobalt (WC-Co), amandla okuguquguquka akhuphuka ngokuqukethwe kwe-cobalt (Co) kuma-alloys e-tungsten-cobalt, kodwa amandla okuguquguquka afinyelela umkhawulo lapho okuqukethwe kwe-cobalt (Co) kufinyelela cishe ku-15%. Amandla e-Flexural akalwa ngesilinganiso sezilinganiso ezimbalwa. Leli nani lizophinda lihluke ngejometri yesampula, isimo esingaphezulu (ubushelelezi), ukucindezelwa kwangaphakathi, kanye nezinkinga zangaphakathi zezinto. Ngakho-ke, amandla e-flexural ayisilinganiso samandla kuphela, futhi amanani e-flexural amandla awakwazi ukusetshenziswa njengesisekelo sokukhetha izinto ezibonakalayo.

I-Porosity

I-carbide enosimende ikhiqizwa inqubo ye-powder metallurgy ngokucindezela nokufaka i-sintering. Ngenxa yemvelo yendlela, ukulandelela amanani e-porosity angase ahlale esakhiweni se-metallurgical yomkhiqizo.

Ukwehliswa kwe-porosity kungathuthukisa ngempumelelo ukusebenza okuphelele komkhiqizo. Inqubo ye-pressure sintering iyindlela ephumelelayo yokunciphisa i-porosity.