Investment Casting Method Research Articles

LIFECASTING IN ARTISTIC CASTING

The paper presents a study of the artistic casting production process starting from a living model. An attempt has been undertaken to develop a technology of creating a copy of human face and head using the materials applied in dental prosthetic. The development of a copying technique for human face and head has been preceded by preparing copies of simpler elements, namely hands and feet. The scope of investigation has included a modification of alginate impression material for the purpose of copying in accordance to the lifecasting method, preparation of an alginate-plaster mould from a living model, then making the plaster replica of the model and secondary silicone-plaster mould. The castings presented in the paper have been finally made of CuSn5Zn5Pb5 tin-zinc-lead bronze by investment casting method. The performed investigative and artistic work has confirmed the suitability of the 'Tropicalgin' material for making a replica of human face according to the lifecasting method. The obtained castings exhibit excellent surface quality despite multiply copying operations.

Microstructure of an experimental Ni base superalloy under various casting conditions

The effect of casting parameters such as melt superheat and solidification rate on the microstructure of an experimental Ni-based superalloy made by vacuum melting and investment casting methods was investigated. The results show that the as cast microstructure of this alloy consists of dendritic γ matrix, interdendritic γ/γ′, γ′ phase, MC carbides and minor phases in interdendritic regions. DSC analyses in addition to SEM and EDS proved that the nodular phase found in minor phases is σ phase, while the η phase was found to solidify in two forms; as plate-like and blocky shape. The volume fraction ( V f) of σ and η phases increases as the melt superheat increases and the solidification cooling rate decreases. Additionally, the V f of interdendritic γ/γ′ increases with higher solidification rate and lower melt superheat. It was found that higher melt superheating temperature enlarges the size of the primary γ dendrites; however the higher solidification rate diminishes it.

Density‐Graded Cellular Aluminum

AbstractOpen‐cell metallic foams with controlled, continuous density gradients were created from polyurethane foam precursors using an investment casting method. This method, designed to improve mass‐efficiency in load‐bearing metallic foams and facilitate bonding of foams to dense materials in higher‐order structures, is described in detail, and demonstrated through pure aluminum foams with model relative density gradients. Methods for structural characterization, including non‐destructive local density mapping, are also illustrated.

Mechanical Properties of Cast Ti-Fe-O-N Alloys

Abstract A recent addition to existing titanium alloys is the Super-TIX™ series (Nippon Steel Corp., Japan), which has intermediate strength between the strengths of CP Ti and Ti-6Al-4V as a result of balancing the Fe, O, and N concentrations. Two alloys in this series were investigated: Ti-1%Fe-0.35%O-0.01%N (Super-TIX800™; LN) and Ti-1%Fe-0.3%O-0.04%N (Super-TIX800N™; HN). These alloys were are-melted and cast using an investment casting method, and their mechanical properties were examined. The yield strength (∼600 MPa) and tensile strength (∼680 MPa) were approximately 33 and 29% higher, respectively, than the corresponding strength of cast CP Ti (ASTM Grade 2). Their percent elongation was somewhat (but not significantly) higher (2–3 %) than that of Ti-6A-4V. On the other hand, the elongation of CP Ti was approximately 7 %. The moduli of elasticity of the alloys ranged from 100–120 GPa. These Ti-Fe-O-N alloys exhibit higher uniaxial yield and tensile strengths than CP Ti, which is currently used for dental applications.

Ultrahigh-Temperature Nb-Silicide-Based Composites

AbstractThis article reviews the most recent progress in the development of Nb-silicide-based in situ composites for potential applications in turbine engines with service temperatures of up to 1350°C. These composites contain high-strength Nb silicides that are toughened by a ductile Nb solid solution. Preliminary composites were derived from binary Nb-Si alloys, while more recent systems are complex and are alloyed with Ti, Hf, W, B, Ge, Cr, and Al. Alloying schemes have been developed to achieve an excellent balance of room-temperature toughness, fatigue-crack-growth behavior, high-temperature creep performance, and oxidation resistance over a broad range of temperatures. Nb-silicide-based composites are described with emphasis on processing, microstructure, and performance. Nb silicide composites have been produced using a range of processing routes, including induction skull melting, investment casting, hot extrusion, and powder metallurgy methods. Nb silicide composite properties are also compared with those of Ni-based superalloys.

Effect of Rare Earth Metals on the Microstructure and Impact Toughness of a Cast 0.4C-5Cr-1.2Mo-1.0V Steel.

Die-making technology directly produced by precise casting technology such as investment and ceramic casting method was a promising technology due to its lower manufacture cost and shorter period in comparison with traditional die-making technology. However, the poor mechanical performance of cast materials, especially low impact toughness, was a main obstacle to the application of cast dies and molds.With a view to improve the impact toughness of CH13 steel (0.4C–5Cr–1.2Mo–1V steel), which was ever used to cast dies for die casting dies, rare earth was added into CH13 steel in our research. It was shown that the dendrite microstructure in CH13 steel had been ameliorated and the segregation ratios of alloying elements were decreased greatly after the addition of rare earth. Grain boundary carbides in MCH13 (CH13 + rare earth) steel had also been inhibited. The impact toughness of MCH13 steel had been improved considerably and the fractography of MCH13 displayed more plastic characteristic. Through thermodynamics and two-dimensional lattice disregistry analysis, it was demonstrated that rare earth inclusions in MCH13 steel act as the heterogeneous nuclei, weaken segregation of alloying elements and improve the impact toughness.