Influence of different factors on material toughness

Žilavost predstavlja kompleksnu karakteristiku materijala koja se može posmatrati sa više aspekata i koja zavisi od mnogo faktora. Vrsta kristalne rešetke, mikrostruktura i hemijski sastav ispitivanog materijala, kao i vrsta epruvete i temperatura ispitivanja, samo su neki od faktora čijom se neznatnom promenom žilavost menja. Zato je veoma važno da se u svakom trenutku može dati ocena žilavosti, odnosno utvrditi žilavo ili krto ponašanje materijala. Instrumentiranjem Šarpijevog klatna, odnosno dodavanjem uređaja koji zapisuje promenu sile i energije sa vremenom napravljen je najveći korak u razvoju metoda za ispitivanje žilavosti. Korišćenjem dopunskih parametara, poput merenja poprečne deformacije posle loma i fraktografskog pregleda, dobijaju se dodatni podaci o mehanizmu loma. U radu je pokazano da se tek poređenjem svih ovih parametara omogućava ocena sklonosti materijala ka krtom lomu, otpornosti na nastanak i rast prsline i potencijalnih mesta nastanka loma.Toughness is a complex material characteristic that is viewed from multiple aspects, and is influenced by numerous factors. An insignificant change in the type of crystal lattice or, e.g. in microstructure, or in the chemical composition of the tested material, as well as in specimen type or the testing temperature, all are but only some of the factors that contribute to the toughness values. It is very important to have the ability to assess toughness, i.e. to determine ductile or brittle material behavior, at any specific time. The largest leap in development of techniques for toughness testing is achieved by instrumenting the Charpy impact testing system with equipment for acquisitioning load and energy versus time data. The use of additional parameters such as: lateral expansion measurements and fractographic evaluation of fractured specimens, reveals more information on the mechanisms behind fracture. The brittle fracture susceptibility and the resistance to crack initiation and propagation assessment, as well as the determination of locations for potential appearance of fracture, have all been treated here by comparing the afore mentioned parameters