Effect Of Solidification Time Research Articles

The Corrosion of Al–Cu-Based Alloys and Comments on the Paper “Effect of Solidification Time on Microstructure, Wettability and Corrosion Properties of A205-T7 Aluminum Alloys” by Amir Kordijazi et al.

Al–Cu-based casting alloys have very high strength, but improper heat treatment will create a material susceptible to stress corrosion failure. A review of this problem is provided and discussed regarding a recent study of A205-T7 alloy castings.

Effect of Solidification Time on Microstructural, Mechanical and Fatigue Properties of Solution Strengthened Ferritic Ductile Iron

Microstructural, mechanical, and fatigue properties of solution strengthened ferritic ductile iron have been evaluated as functions of different solidification times. Three types of cast samples with increasing thickness have been produced in a green sand automatic molding line. Microstructural analyses have been performed in order to evaluate the graphite nodules parameter and matrix structure. Tensile and fatigue tests have been carried out using specimens taken from specific zones, with increasing solidification time, inside each cast sample. Finally, the fatigue fracture surfaces have been observed using a scanning electron microscope (SEM). The results showed that solidification time has a significant effect on the microstructure and mechanical properties of solution strengthened ferritic ductile iron. In particular, it has been found that with increasing solidification times, the microstructure becomes coarser and the presence of defects increases. Moreover, the lower the cooling rate, the lower the tensile and fatigue properties measured. Since in an overall casting geometry, same thicknesses may be characterized by different microstructures and mechanical properties induced by different solidification times, it is thought that the proposed methodology will be useful in the future to estimate the fatigue strength of cast iron castings through the numerical calculation of the solidification time.

Effect of magnetic field during the liquid – solid phase transition of some thermoplastic polymers

Application of external fields on a polymer is common physical treatment for modifying the polymer properties. The field is applied on the final polymeric object or during synthesising or polymerization. In this work, the magnetic field from powerful permanent magnets was applied during the phase transition from liquid to solid phase, where the polymer chain inter-attraction forces are minimal. So, magnetic fields with less strength may perform valuable structural variations. It is found that magnetic field of 355 mT accelerated the spherulite growth in polyethylene glycol (PEG) films. High density polyethylene (HDPE) of zigzag chain, polypropylene (PP) of chains with side group and polystyrene (PS) as glassy polymer with ring, were magnetically treated with different field strength during their phase transition. Treated and untreated film samples were tested physically. IR- spectroscopy, X-ray diffraction, DTA, DSC and tensile stress – strain testing techniques were used in order to characterize, quantitatively, most types of the occurred variations if any. PS samples were casted by hot pressing and from dilute solution in magnetic field in order to detect the effect of solidification time on the size of the magnetic induced variations. Properties of treated HDPE showed little swinging about the untreated value in the field strength up to 160 mT. PP properties showed serious variations in the same range of field strength. PS films casted from dilute solution showed stronger variations than the films casted by hot pressing of the melted PS. All data are presented in coloured graphs. Spherulites images are extracted from a video clip that is used in measuring the rate of PEG spherulite growth in magnetic fields.

The effect of solidification time and heat treatment on the fatigue properties of a cast 319 aluminum alloy

Solidification time and heat treatment are known to have a large effect on the microstructure of cast aluminum alloys. This study was conducted to quantify how the fatigue properties of a 319-type aluminum alloy are affected by solidification time and heat treatment. Both porosity-containing (non-hot isostatically pressed (HIP)) and porosity-free (HIP) samples in the T6 (“peak aged”) or T7 (“overaged”) heattreated conditions were tested. As the solidification time increased, the average initiating pore diameter increased and stress-controlled fatigue life decreased. Heat treatment was observed to have a large effect on fatigue properties of the HIP samples. However, in the non-HIP fatigue samples, heat treatment did not significantly change the fatigue life or fatigue strength of the cast 319-type alloy. The absence of an influence of heat treatment on fatigue response is attributed to the predominance of the microporosity in fatigue crack initiation in cast aluminum.

Effect of solidification time on the structural evolution of undercooled single phase alloys

The Cu 70Ni 30 alloy melt was bulk undercooled by combining the glass fluxing technique with superheating–cooling cycles. Different solidification times, ranging from several seconds to several hundred seconds, were designed to investigate the structural evolution of the alloy in the undercooling range 0–250 K. The grain refinements at low and high undercoolings were all observed for all values of solidification time. The results indicate that the grain refinement at low undercoolings mainly originates from the dendrite remelting driven by the chemical superheating rather than by solid–liquid interface energy, and that at high undercoolings the refinement is not related to the dendrite remelting at all.

Effect of solidification time on the microstructure and physical properties of dental gold casting alloys.

SYNOPSIS IN INTERLINGUA LE EFFECTO DEL TEMPORE DE SOLIDIFICATION SUPER LE MICROSTRUCTURA E LE PROPRIETATES PHYSIC DE ALLIGATOS FUSIONAL DE AURO DENTAL.-Esseva determinate: le longor del tempore requirite pro obtener solidification, le dimensiones del grano, le duritate de Vicker, le grado de porositate, e limite del elasticitate in flexion, e le modulo del elasticitate de specimens de alligato de auro dental fusionate a 5 differentes temperaturas. Le resultatos indica que fundition a alte temperatura prologa le solidification del alligato e resulta in un producto con plus grossier structura granular, plus basse duritate, e extense porositate, e plus basse limites de elasticitate que productos fusionate a plus basse temperaturas.