Study on Microstructure and Phase Composition of Co-8.8Al-9.8W Superalloy with Alloying Element Tantalum

2015 ◽  
Vol 1083 ◽  
pp. 37-39
Author(s):  
Yang Tao Xu ◽  
Qi Zhen Sha ◽  
Wan Li Zhao
Keyword(s):  
Phase Composition ◽  
Ball Mill ◽  
Melting Process ◽  
Xrd Analysis ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Pure Element ◽  
Alloying Element ◽  
Etching Solution ◽  
Electrolytic Etching

In order to study the effect of tantalum to the microstructure and phase composition of Co-8.8Al-9.8W-XTa (X=0,2,at%) superalloy. The Co-8.8Al-9.8W-XTa (X=0,2) supperalloy used pure element powder, according to the ratio of different atomic percentage composition to make ingredients. It is mixed by planetary ball mill, pressed into blocks after the melting shape. Vacuum induction melting process was prepared by melting, after grinding, polishing, and after a volume of 5% perchloric acid and 95% of the electrolytic etching solution prepared in ethanol corrosion observed after analysis of the microstructure and phase composition by OM and XRD analysis. It can be found that the 9.8W and 2Ta alloy were mainly composed of rich γ-Co matrix of austenite precipitation of γ phase and coherent with matrix of the L12 structure of γ′-Co3(Al,W) phase. In addition, Ta element has effect on grain refinement and the number of γ′-Co3(Al,W) phase refines grain.

Alloying Element Nb Effect on Microstructure of Co-Al-W Superalloy by Vacuum Arc Melting

2012 ◽  
Vol 229-231 ◽  
pp. 63-67
Author(s):  
Yang Tao Xu ◽  
Tian Dong Xia ◽  
Wen Jun Zhao ◽  
Xiao Jun Wang
Keyword(s):  
Hardness Test ◽  
Melting Process ◽  
Xrd Analysis ◽  
Vacuum Arc ◽  
Rockwell Hardness ◽  
Pure Element ◽  
Alloying Element ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
L12 Structure

Co-Al-W supperalloy used pure element powder, according to the ratio of different atomic percentage composition to make ingredients. It is mixed by planetary ball mill, pressed into blocks after the melting shape. Vacuum arc melting process was prepared by melting, after grinding, polishing, and after a volume of 5% perchloric acid and 95% of the electrolytic etcheing solution prepared in ethanol corrosion observed after analysis of the microstructure and phase composition by XRD analysis .It can be found that Co-Al-W superalloys were mainly composed of cobalt-rich matrix of austenite precipitation of γ phase and coherent with matrix of the L12 structure of γ′-Co3(Al,W) phase. In addition, Nb have effect on grain refinement and refine grain. Rockwell hardness test and analysis, It can be found that Nb can clearly improve the Co-Al-W superalloy hardness.

Vacuum Induction Melting and Investment Casting Technologies Tailored to Near-Gamma TiAl Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 1463-1468 ◽  
Author(s):  
Antonín Dlouhý ◽  
Kateřina Dočekalová ◽  
Ladislav Zemčík
Keyword(s):  
Investment Casting ◽  
Cost Effective ◽  
Melting Process ◽  
Vacuum Induction Melting ◽  
Crucible Wall ◽  
Induction Melting ◽  
Ceramic Shell ◽  
Shell Mould ◽  
Stress States ◽  
As Stress

The present study focuses on vacuum induction melting and investment casting of neargamma TiAl intermetallic alloys. The attention is mainly given to a cost-effective melting process in which a primary alloy ingot is re-melted in a ceramic crucible and cast into a ceramic shell mould. Two types of crucibles (based on Al2O3 and Y2O3) are considered. The most detrimental reactions that govern the contamination of the molten alloy with ceramic particles were determined. Results suggest that the crucible wall attack can be considerably limited by using either the Y2O3 (with no SiO2-type binder) or Al2O3 crucibles with a suitable coating. After pouring, a mechanical interaction associated with different thermal expansions of TiAl casts and ceramic shell moulds can result in serious product damage. A simple 1D-1D model of the cooling process was formulated and the heat flow as well as stress states in the cast-mould system were numerically solved. Process parameters (melt superheat, initial mould temperature, cooling kinetics and mould composition) were optimized in order to reduce the stress in the casts. The optimized parameters delimited a processing window in which complex-shaped TiAl castings like turbocharger wheels can be fabricated.

scholarly journals EFFECT OF SCRAP USING IN CHARGE ON THE STRUCTURE AND PROPERTIES OF ZhS6U NICKEL-BASED SUPERALLOY. PART 1. MICROSTRUCTURE ANALYSIS AND PHASE COMPOSITION OF ZhS6U ALLOY PREPARED WITH SCRAP

2019 ◽  
Vol 62 (5) ◽  
pp. 360-365 ◽  
Author(s):  
A. V. Koltygin ◽  
V. E. Bazhenov ◽  
A. I. Bazlov ◽  
T. A. Bazlova ◽  
V. D. Belov
Keyword(s):  
Phase Composition ◽  
Raw Material ◽  
Alloying Elements ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Ceramic Mold ◽  
Nickel Base Superalloy ◽  
Induction Melting ◽  
Gating System ◽  
Turbine Engine

Expensive nickel superalloys are used for manufacture of cast blades of gas turbine engine (GTE). However, for the blades only a small amount of alloy was used and the remainder is used for gating system. Therefore, the most proportion of alloy after casting is a scrap, the use of which as raw material for blades production significantly reduces their cost. However, the use of scrap is associated with some risks: the possibility of alloy contamination by nonmetallic inclusions and loss of alloying elements. So, the investigation of a scrap usage effect on the blades properties is very important. In the first part of article the influence of the scrap amount on the microstructure and phase composition of the ZhS6U-VI nickel-base superalloy were examined. The GTE blades samples, fully produced from the scrap of ZhS6U-VI superalloy by investment casting were investigated. The scrap before using was cleaned from contaminations and ceramic mold remains. Samples were cut from blade dowetail and gating system near dowetail. In addition, cylindrical samples that were casted into the copper mold from the virgin alloy ZhS6U-VI without the scrap and from alloys with 50 % and 100 % of scrap were researched. The alloys microstructures were investigated using scanning electron microscopy and optical microscopy. The phase’s identification was carried out using the energy-dispersive X-ray spectroscopy (EDS) and the calculations of phase composition were made by Thermo-Calc software and literature data about phases in nickel-based superalloys. Content of alloying elements (except carbon) was measured by EDS analysis. The studies were carried out on the samples as-casted and annealed for 4 hours at 1210 °C. It is shown that the use of scrap does not fundamentally change the alloy phase composition at both during vacuum induction melting and vacuum arc melting.

Processing and Characterization of Superinvar for Space Application

2015 ◽  
Vol 830-831 ◽  
pp. 30-33 ◽  
Author(s):  
Rohit Kumar Gupta ◽  
Praveen Varma ◽  
V. Anil Kumar ◽  
P. Sarkar ◽  
Jaimin Desai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Thermomechanical Processing ◽  
Coefficient Of Thermal Expansion ◽  
Melting Process ◽  
Processing Parameters ◽  
Raw Material ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Process Selection

Material with ultra-low coefficient of thermal expansion (CTE) is required for mounting camera and other optical elements in satellite systems. Invar (64 Fe 36Ni) has been the work-horse material for this purpose. In recent years, modified version of conventional invar i.e. Superinvar with 5% cobalt (replacing 5% nickel) is being used to further bring down the errors in camera mountings due to thermal expansion. Processing of this alloy poses many challenges due to its requirement of ultra-low CTE. In the present work, melting and thermomechanical processing parameters were selected to meet the specified requirement of the alloy. The alloy was melted through vacuum induction melting process to obtain uniform and homogeneous chemistry and properties. Virgin raw material was used to achieve lowest carbon and manganese contents. Chemical composition thus obtained is found to be within the specification. Material was hot worked to refine the microstructure. Three different sizes of forged blocks were produced. Hot worked material was heat treated to obtain desirable and stable microstructure. Heat treatment cycle for stabilization was selected and used to retain carbon in the solution and minimize temporal growth. Mechanical properties (tensile strength and modulus of elasticity) and physical properties (CTE, thermal conductivity) were evaluated. Properties were found to be meeting the specification. It is observed that the material shows uniform single phase austenitic microstructure. The paper presents details of the process selection and challenges in processing of this alloy to obtain the targeted CTE < 0.6x10-6 per °C in the temperature range of 25°C to 150°C along with other desired mechanical properties.

THE INFLUENCES OF MANUFACTURING TECHNOLOGY OF THE MAGNETRON TARGETS ON THE MICROSTRUCTURE AND PHASE COMPOSITION OF Zr–Y-BASED ALLOY

2021 ◽  
pp. 118-127
Author(s):  
R.M. Nazarkin ◽  
◽  
A.V. Platitsin ◽  
E.B. Chabina ◽  
◽  
...  
Keyword(s):  
Phase Composition ◽  
Chemical Deposition ◽  
Ceramic Coatings ◽  
Manufacturing Technology ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
The Comparative Study

The Zr–Y-based alloy targets are used for spraying of heat-resisting ceramic coatings on the gas-turbine hot section components surface by the plasma-chemical deposition techniques. The comparative study of the microstructure and phase composition for target specimens, which manufactured by vacuum-induction melting or vacuum-arc melting, are performed. The patterns of change in a microstructure and a phase composition in the experimental Zr–Y-based alloy, depending of manufacturing technology are shown. The aspects which have led to transformation of microstructure and phase composition of VTsM-1 Zr–Y-based alloy at the change of the manufacturing technology of targets are detected.

Desulfurization Mechanism of K4169 Superalloy Using CaO Crucible in Vacuum Induction Melting Process

2018 ◽  
pp. 575-586
Author(s):  
Kewei Xie ◽  
Bo Chen ◽  
Mengshu Zhang ◽  
Zhanhui Du ◽  
Xiangdong Zha ◽  
...  
Keyword(s):  
Melting Process ◽  
Vacuum Induction Melting ◽  
Induction Melting
Sign in / Sign up

Export Citation Format

Share Document