Paper describes superplastic behaviour of the Al-4.5Mg-0.46Mn-0.44Sc alloy. Alloy was produced by casting and conventionally processed to form a sheet with thickness of 1.9 mm and average grain size of 0.011 mm. The superplastic properties of the alloy were investigated using uniaxial tensile test with a constant cross-head speed and strain rate in range 1x10-4 to 5x10-2s-1 at temperatures from 390 to 550°C. Iinvestigations included determinations of the true-stress, true-strain characteristics, the max. elongations to failure, strain-rate sensitivity indexes m and microstructure of the alloy.
COBISS.SI-ID: 1004639
A comprehensive study of 18% Ni maraging steel welds is done in order to determine the suitability of repair welding of aluminum die-casting dies and to prolong the in-service tool life. This study emphasizes the influence of welding parameters and post-welding precipitation annealing heat treatment on the welds' mechanical and metallurgical properties.
COBISS.SI-ID: 10944795
Al86Mn3Be11 alloy cast into Cu mould was subjected to investigation. The as-cast microstructure consisted of a quasicrystalline icosahedral phase (i-phase), Be4AlMn phase and, a hexagonal phase. The Al represented the dominant phase. Chemical compositions of phases were determined using AES. The composition of Be4AlMn slightly deviated from the stoichiometric composition, whereas the composition of i-phase was approx. Al52Mn18Be30. The average composition of the hexagonal phase was Al66Mn21Be13. Deep etching and particle extraction enabled a study of 3D morphology of i- and hexagonal phase.
COBISS.SI-ID: 13052182
Force that acts on the punch during fine-blanking of parts to be used in turbochargers for automotive diesel engines was measured. The aim of research was to define the time dependence of force and vertical movement of the punch at the same time. The influences of different heat treatment procedures on mechanical properties of Inconel 718 alloy that are reflected in the loading on the tool were investigated. Temperature of solution annealing affects the amount of ? phase which is present in the Ni matrix and mechanical properties.
COBISS.SI-ID: 942175
The reduction of area in the through thickness direction is an essential mechanical property of thick steel heavy plates. By a routine control, a very small through thickness reduction of area was found for tensile specimen of a 90 mm plate. Careful investigations of the fracture and section of specimens cut from the as solidified continuously cast 250 mm thick slab showed that the cause was the presence of coarse particles of niobium carbonitride as constituent of the quasi eutectic Fe-Nb(C, N) that form because of the centerline segregation of Nb.