scholarly journals Solidification Process and Volume Fraction in Sn-Ag-Cu Alloy

2010 ◽  
Vol 13 (7) ◽  
pp. 521-530 ◽  
Author(s):  
Yoshiko Takamatsu ◽  
Hisao Esaka ◽  
Kei Shinozuka
Keyword(s):  
Volume Fraction ◽  
Solidification Process ◽  
Cu Alloy

Shape Memory Characteristics and Superelasticity of Ti-Ni-Cu Alloy Ribbons with Nano Ti2Ni Particles

2008 ◽  
Vol 8 (2) ◽  
pp. 722-727 ◽  
Author(s):  
Tae-hyun Nam ◽  
Cheol-am Yu ◽  
Jung-min Nam ◽  
Hyun-gon Kim ◽  
Yeon-wook Kim
Keyword(s):  
Melt Spinning ◽  
Volume Fraction ◽  
Deformation Behaviour ◽  
Parent Phase ◽  
Tensile Tests ◽  
Constant Load ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Average Size ◽  
Memory Characteristics

Microstructures and deformation behaviour of Ti-45Ni-5Cu and Ti-46Ni-5Cu alloy ribbons prepared by melt spinning were investigated by transmission electron microscopy, thermal cycling tests under constant load and tensile tests. Spherical Ti2Ni particles coherent with the B2 parent phase were observed in the alloy ribbons when the melt spinning temperature was higher than 1773 K. Average size of Ti2Ni particles in the ribbons obtained at 1873 K was 8 nm, which was smaller than that (10 nm) in the ribbons obtained at 1773 K. Volume fraction of Ti2Ni phase in the ribbons obtained at 1873 K was 40%, which was larger than that (20%) in the ribbons obtained at 1773 K. The stress required at temperatures of Af + 10 K for the stress-induced martensitic transformation increased from 93 MPa to 229 MPa and apparent elastic modulus of the B2 parent phase increased from 56 GPa to 250 GPa with increasing the melt spinning temperature from 1673 K to 1873 K in Ti-45Ni-5Cu alloy ribbons. The critical stress for slip deformation of the ribbons increased by coherent Ti2Ni particles, and thus residual elongation did not occur even at 160 MPa, while considerable plastic deformation occurred at 60 MPa in the ribbons without Ti2Ni particles. Almost perfect superelastic recovery was found in the ribbons with coherent Ti2Ni particles, while only partial superelastic recovery was observed in the ribbons without coherent Ti2Ni particles.

A Volume-of-Fluid Based Numerical Simulation of Solidification in Binary Alloys on Fixed Non-Uniform Co-Located Grids

2009 ◽  
Author(s):  
Mehdi Farrokhnejad ◽  
Anthony G. Straatman ◽  
Jeffrey T. Wood
Keyword(s):  
Volume Fraction ◽  
Binary Alloys ◽  
Solidification Process ◽  
Casting Process ◽  
Reconstruction Algorithm ◽  
Volume Of Fluid ◽  
Mold Filling ◽  
Mg Alloys ◽  
Uniform Grid ◽  
Spurious Currents

In this paper, the authors present a platform for the modeling of mold filling and solidification of binary alloys with properties similar to Mg alloys. A volume-of-fluid (VOF) based method is used to capture the interface between solid and liquid in binary alloys solidification process on a fixed non-uniform grid, developed for implementation in a colocated finite volume framework. Contrary to other works, to update the volume fraction (of fluid) in the field, a link between source-based type of energy equation and VOF reconstruction algorithm is described and implemented. A new approximation to the pressure gradient is presented to remove all ‘Spurious Currents’ [1] resulting from pressure jumps in the vicinity of the interface. Based upon the work presented, it is concluded that the present combination of the equations are not only computationally straightforward to implement and upgrade to a 3D problem, but also provides an excellent platform to capture the interface between constituents in a die-casting process including solidification and mold filling process. The current framework will be used in future works to characterize the local mechanical properties of Mg alloys by using information from simulation at the dendritic level.

Three Strategies to Achieve Concurrent Strengthening by Ultrafine-Grained and Precipitation Hardenings for Severely Deformed Age-Hardnable Aluminum Alloys

2016 ◽  
Vol 1135 ◽  
pp. 161-166 ◽  
Author(s):  
Shoichi Hirosawa ◽  
Yong Peng Tang ◽  
Zenji Horita ◽  
Seung Won Lee ◽  
Kenji Matsuda ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Age Hardening ◽  
Cu Alloy ◽  
Ultrafine Grained ◽  
Δ Phase ◽  
Microalloying Elements ◽  
Wrought Aluminum Alloys

In this paper, comprehensive studies on the age-hardening behavior and precipitate microstructures of severely deformed and then artificially aged aluminum alloys have been conducted to clarify whether or not concurrent strengthening by ultrafine-grained and precipitation hardenings can be achieved. From our graphically-illustrated equivalent strain dependence of both the attained hardness and increment/decrement in hardness during aging (i.e. age-hardenability), three strategies to maximize the combined processing of severe plastic deformation and age-hardening technique are proposed. (1) Lowering of aging temperature and (2) utilization of microalloying elements can improve not only the attained hardness but also the age-hardenability of high-pressure torsion (HPT) specimens of Al-Mg-Si (-Cu) alloy due to the increased volume fraction of transgranular precipitates. A further increase in hardness can be achieved by (3) taking advantage of spinodal decomposition for HPTed Al-Li-Cu alloy, in which nanoscale precipitates of δ’ phase are successfully formed within ultrafine grains, irrespective of the higher number density of grain boundaries. The attained hardness of >HV290 in the latter alloy is almost the highest among conventional wrought aluminum alloys, and therefore our proposed strategies will be useful for designing concurrently strengthened severely-deformed age-hardenable aluminum alloys.

Course of Solidification Process of AlMMC – Comparison of Computer Simulations and Experimental Casting

2012 ◽  
Vol 191 ◽  
pp. 89-98
Author(s):  
Roman Zagórski ◽  
Anna J. Dolata ◽  
Maciej Dyzia
Keyword(s):  
Experimental Data ◽  
Temperature Distribution ◽  
Volume Fraction ◽  
Aluminum Matrix ◽  
Solidification Process ◽  
Sand Mold ◽  
Phase System ◽  
Discrete Phase Model ◽  
Composite Matrix ◽  
Solidification Temperature

The aim of the paper is to present the possibilities of computational simulations for the casting of aluminum matrix composite (AlMMC) reinforced with ceramics based on experimental data. The comparison of simulation and experimental results concerned the solidification process i.e. the course of solidification, temperature distribution and final arrangement of reinforcement particles. First, we have performed the experimental gravity casting of the aluminum matrix alloy AK12 (AlSi12CuNiMg2) and the composites AK12/SiC and AK12/Cg reinforced with silicon carbide SiC and glass carbon Cg, respectively, into the sand mold. During the experiment we have recorded the temperature using the ThermaCAM photometer system as well as in the selected point inside the sand mold. Using experimental data we have carried out the numerical calculations according to the methods and procedures contained in the program ANSYS Fluent 13. We have based the simulations on the two-dimensional model in which the Volume of Fluid (VOF) and enthalpy methods have been applied. The former is to describe two-phase system (air-composite matrix free surface, volume fraction of particular continuous phase) and the latter shows modeling of the solidification process of the alloy and composite matrix. We have used the Discrete Phase Model (DPM) to depict the presence of reinforcement particles. The assumption of the appropriate values of simulation parameters has shown that the simulation results are convergent with experimental ones. We have observed a similar course of the composite solidification (temperature change at the designated point), the temperature distribution and the arrangement of reinforcement particles for the simulation and experiment.

scholarly journals Structural Investigations of Solidification and Heat Treatments Influence on High Alloyed Cast Irons Grades with Nb-V-Ti Additions

2009 ◽  
Vol 289-292 ◽  
pp. 77-86 ◽  
Author(s):  
Jacqueline Lecomte-Beckers ◽  
Jérôme Tchoufang Tchuindjang
Keyword(s):  
Phase Transformations ◽  
Volume Fraction ◽  
Raw Materials ◽  
Solidification Process ◽  
Heat Treatments ◽  
Hot Strip Mill ◽  
Cast Irons ◽  
Structural Investigations ◽  
Alloyed Cast ◽  
The Matrix

Two High Alloyed Cast Irons (HACI) were studied, both belonging to the Fe-C-Cr-Si-X system where X represented a strong carbide forming element. One of these alloys was obtained after adding Nb, V and Ti to the chemical composition of the other alloy. Raw materials originated from spun cast rolls for hot strip mill were submitted to different heat treatments routes, in order to study the influence of alloying elements on the microstructure. Both HACI grades contained a mixture of martensite and retained austenite matrix in the as-cast conditions and after quenching. Differential Thermal Analysis was carried out on the heat treated samples in order to determine the phase transformations occurring during re-melting and subsequent solidification sequence. Diffusionless transformations leading to various types of martensite were found in the matrix. Bulky NbC carbides precipitating at the beginning of the solidification process strongly influence the nature and the rate of the subsequent diffusional phase transformations, particularly for HACI grade with Nb, V and Ti additions. Quantitative metallography was done to determine graphite, NbC carbides, cementite and matrix volume fraction in HACI studied grades.

Effect of Si on As-Cast Microstructure in Quasicrystalline Al-Cu -Fe Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 619-622 ◽  
Author(s):  
Jin Shan Zhang ◽  
Yong Jun Xue ◽  
You Jun Guo ◽  
Chun Xiang Xu ◽  
Wei Liang
Keyword(s):  
Volume Fraction ◽  
Solidification Process ◽  
Quasicrystalline Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Casting ◽  
Β Phase ◽  
Ω Phase ◽  
Icosahedral Quasicrystalline ◽  
Scanning Electron

Effect of Si on the forming ability of quasicrystalline phase in Al65Cu20Fe15 alloys fabricated under conventional casting conditions has been studied using X-ray diffraction (XRD), optical microscopy (OM), and scanning electron microscopy (SEM). The results show that under the conventional casting conditions, it is found that the addition of certain amount of Si into the Al-Cu-Fe melts can change the formation of Al62.5Cu25Fe12.5 quasicrystals during the solidification process. Compared with Al65Cu20Fe15 alloy, Al64.5Cu20Fe15Si0.5 alloy has smaller volume fraction of β phase solidifying initially, larger volume fraction of the quasicrystal phase generating in the subsequent peritectic reaction, and larger volume fraction of ω phase solidifying finally. Both experimental results and the theory of Hume-Rothery show that addition of Si can promote the formation ability of the icosahedral quasicrystalline Al62.5Cu25Fe12.5 phase in Al-Cu-Fe alloy.

The Effect of Thermal Treatment on the Microstructural Evolution of an Al-Cu Alloy

2003 ◽  
Author(s):  
Tracie L. Zoeller ◽  
Thomas H. Sanders
Keyword(s):  
Aluminum Alloy ◽  
Chemical Composition ◽  
Marked Effect ◽  
Volume Fraction ◽  
Solidification Rate ◽  
Thermal Treatments ◽  
Large Volume Fraction ◽  
Cu Alloy ◽  
Processing Step ◽  
Alloy Microstructure

Following solidification, an aluminum alloy microstructure is highly segregated. The microstructure consists of cored dendrites with various soluble and insoluble phases present in the dendritic regions. The solidification rate has a marked effect on the amount of coring that an alloy experiences. Understanding the effects of the solidification rate is important in explaining differences in microstructures. Subsequent heat treatments are performed to homogenize the microstructure. The microstructure evolution after each processing step is dependent upon the previous microstructures. The variation in local chemical composition may promote or hinder precipitation of new phases. A large volume fraction of coarse insoluble phases can lead to the occurrence of recrystallized grains via particle stimulated nucleation, while inhomogeneous solute distribution can lead to the precipitation of an uneven distribution of dispersoid phases. The effect of solidification rate and subsequent thermal treatments on the microstructure of an Al-4Cu alloy will be investigated and experimental and numerical results will be presented.

scholarly journals Niobium Additions to a 15%Cr–3%C White Iron and Its Effects on the Microstructure and on Abrasive Wear Behavior

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1321 ◽  
Author(s):  
Arnoldo Bedolla-Jacuinde ◽  
Francisco Guerra ◽  
Ignacio Mejia ◽  
Uzzi Vera
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Abrasive Wear ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Solidification Process ◽  
White Iron ◽  
Bulk Hardness ◽  
Abrasive Wear Behavior ◽  
Cast Alloys

From the present study, niobium additions of 1.79% and 3.98% were added to a 15% Cr–3% C white iron, and their effects on the microstructure, hardness and abrasive wear were analyzed. The experimental irons were melted in an open induction furnace and cast into sand molds to obtain bars of 45 mm diameter. The alloys were characterized by optical and electron microscopy, and X-ray diffraction. Bulk hardness was measured in the as-cast conditions and after a destabilization heat treatment at 900 °C for 30 min. Abrasive wear resistance tests were undertaken for the different irons according to the ASTM G65 standard in both as-cast and heat-treated conditions under three loads (58, 75 and 93 N). The results show that niobium additions caused a decrease in the carbon content in the alloy and that some carbon is also consumed by forming niobium carbides at the beginning of the solidification process; thus decreasing the eutectic M7C3 carbide volume fraction (CVF) from 30% for the base iron to 24% for the iron with 3.98% Nb. However, the overall carbide content was constant at 30%; bulk hardness changed from 48 to 55 hardness Rockwell C (HRC) and the wear resistance was found to have an interesting behavior. At the lowest load, wear resistance for the base iron was 50% lower than that for the 3.98% Nb iron, which is attributed to the presence of hard NbC. However, at the highest load, the wear behavior was quite similar for all the irons, and it was attributed to a severe carbide cracking phenomenon, particularly in the as-cast alloys. After the destabilization heat treatment, the wear resistance was higher for the 3.98% Nb iron at any load; however, at the highest load, not much difference in wear resistance was observed. Such a behavior is discussed in terms of the carbide volume fraction (CVF), the amount of niobium carbides, the amount of martensite/austenite in matrix and the amount of secondary carbides precipitated during the destabilization heat treatment.

On the Influences of Adjacent Conducting Media and Coil Frequency on the Electromagnetic Field and Flow Characteristics in Solidifying Melts

2015 ◽  
Vol 15 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Gregory Poole ◽  
Laurentiu Nastac
Keyword(s):  
Electromagnetic Field ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Solidification Process ◽  
Mushy Region ◽  
Zone Model ◽  
Low Frequencies ◽  
Electrically Conducting ◽  
Cu Alloy ◽  
Chill Mold

AbstractThis paper examines the electromagnetic and flow field modification caused by the placement of electrically conducting media in the vicinity of the coil and molten metal and the corresponding influences of coil operating frequency. The electromagnetic field characteristics were numerically calculated using the mutual inductance technique. An improved dual-zone model was employed to describe flow behavior in the mushy region, and accounts for flow damping via interactions between the crystallites and the turbulent eddies. Calculations were performed for unidirectional solidification of an Al-4.5 wt% Cu alloy in a bottom-chill mold undergoing EM stirring. It was found that the presence of shields greatly modified the Lorentz force distribution within the melt. This led to noteworthy changes in the flow directionality, as well as changes in the spatial variation of temperature as solidification progressed. It was also found that these effects were most pronounced at low frequencies. The significance of these findings with respect to solidification process design will be discussed.

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