Does the casting mode influence microstructure, fracture and properties of different metal ceramic alloys?

Abstract

The aim of the present study was to evaluate the tensile strength, elongation, microhardness, microstructure and fracture pattern of various metal ceramic alloys cast under different casting conditions. Two Ni-Cr alloys, Co-Cr and Pd-Ag were used. The casting conditions were as follows: electromagnetic induction under argon atmosphere, vacuum, using blowtorch without atmosphere control. For each condition, 16 specimens, each measuring 25 mm long and 2.5 mm in diameter, were obtained. Ultimate tensile strength (UTS) and elongation (EL) tests were performed using a Kratos machine. Vickers Microhardness (VM), fracture mode and microstructure were analyzed by SEM. UTS, EL and VM data were statistically analyzed using ANOVA. For UTS, alloy composition had a direct influence on casting condition of alloys (Wiron 99 and Remanium CD), with higher values shown when cast with Flame/Air (p < 0.05). The factors 'alloy" and 'casting condition" influenced the EL and VM results, generally presenting opposite results, i.e., alloy with high elongation value had lower hardness (Wiron 99), and casting condition with the lowest EL values had the highest VM values (blowtorch). Both factors had significant influence on the properties evaluated, and prosthetic laboratories should select the appropriate casting method for each alloy composition to obtain the desired property.

Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement

“…Due to the different microhardness values of the alloys, the resultant roughness of this airborne particle abrasion may be different for each type of alloy. However, several studies have shown that some of these alloys have very close microhardness values (9,24,25) and in the present study, different bond strength values were found with the same resin cement.…”

Annealing of Co-Cr dental alloy: effects on nanostructure and Rockwell hardness

“…Bauer et al13 demonstrated that when noble and basic alloys are cast in an uncontrolled environment, the metals are exposed to deleterious gases and elements, which influence their mechanical properties such as internal porosity. DMLS is a new technology in dentistry for manufacturing Co-Cr metal ceramic substructures, and therefore, the steps of the procedure and the factors that affect product quality are not well known.…”

“…Moreover, the quality of a material and thus the clinical chances of success are directly affected by controlling the manufacturing environment 13-15. New manufacturing processes such as metal injection molding and powder-metallurgical techniques are being developed to achieve dental alloys with better microstructure and mechanical properties 10,16.…”

Effect of PFM Firing Cycles on the Mechanical Properties, Phase Composition, and Microstructure of Nickel‐Chromium Alloy

“…In the microstructure of group 2 specimens, some precipitates, which were probably constituents of chromium, molybdenum, niobioum, and silicon carbides, were also observed in the dendritic region . The microstructure in this group also started to reveal the grain boundaries partially.…”

“…High‐temperature heat treatments and repeated PFM firing cycles have been shown to affect alloy microstructures, surface oxides, corrosion, and physical and mechanical properties. To date, few studies have evaluated the effects of high temperature attained during PFM firing on the mechanical properties and microstructure of Ni‐Cr alloy . However, no study has been carried out to evaluate the changes in mechanical properties, microstructure, and X‐ray diffraction (XRD) pattern of the alloy after each firing.…”