scholarly journals Microstructures and Properties of V-Modified A380 Aluminum Alloy Produced by High Pressure Rheo-Squeeze Casting with Compound Field Treatment

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 587
Author(s):  
Chong Lin ◽  
Hanxin Chen ◽  
Li Zeng ◽  
Shusen Wu ◽  
Xiaogang Fang
Keyword(s):  
High Pressure ◽  
Aluminum Alloy ◽  
Fine Particle ◽  
Quality Index ◽  
Squeeze Casting ◽  
Volume Fraction ◽  
Average Length ◽  
Gravity Casting ◽  
A380 Alloy ◽  
Heat Treated

The melt of V-modified A380 alloy aluminum alloy was treated by compound field of ultrasonic vibration (UV) and electromagnetic stirring (ES) around liquidus temperatures. Then the high pressure rheo-squeeze casting (HPRSC) process was used to produce an ingot with the alloy melt obtained. The results indicate that the polygonal Si2V phase is precipitated after adding vanadium to the alloy. With the increasing of V content from 0 to 1.05%, the average length and volume fraction of β-Al5FeSi phase is decreased to 30 μm and 1.44%, respectively. The refinement effects of UV, ES, and UV-ES compound field on the microstructure of the gravity casting alloy are as follows: UV-ES > UV > ES. When the pressure is increased from 0 to 400 MPa, the size of primary α-Al is decreased gradually, the morphology of β-Al5FeSi phase is changed from an acicular to a fine fibrous-like one, and the polygonal Si2V phase is refined to fine particle with an average grain diameter of about 8 μm. The ultimate tensile strength (UTS), yield strength (YS), and elongation of the alloy without V are lower than that of the alloy with 0.7%V under the same pressure. When the pressure is 400 MPa, the UTS, YS, and elongation of T6 heat-treated HPRSC alloy with 0.7%V are 301 MPa, 182 MPa, and 3.3%, respectively. With the decrease in the length of β-Al5FeSi phase, the quality index of the HPRSC alloy is increased.

Effect of the Pressure on Microstructure of A380 Aluminum Alloy Prepared by Squeeze Casting

2017 ◽  
Vol 735 ◽  
pp. 59-64
Author(s):  
Bai Shui Yu ◽  
Shu Ming Xing
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Grain Boundary ◽  
Squeeze Casting ◽  
Volume Fraction ◽  
Chinese Script ◽  
Squeeze Pressure ◽  
Tissue Volume ◽  
A380 Alloy ◽  
Solidification Pressure

Effects of the solidification pressure on microstructure and mechanical properties of A380 alloy have been experimentally investigated. The obtained results show that the microstructures of the A380 aluminum alloy is fined, the porosity is decreased and the mechanical properties is improved remarkably with the increase of the solidification pressure. When the squeeze pressure increases from 0 MPa to 75MPa, the size of dendrite arm space decreases from 914 μm to 313 μm, reduced by 66%; the eutectic tissue volume fraction increases from 22.5% to 41.36%; the porosity decreases from 4.91% to 1.23%; the secondary dendrite spacing decreases from 39 μm to 18 μm; the size of needle-like β-Al5FeSi phase decreases significantly, and a few Chinese script α-Fe phases was observed in the grain boundary.

Alloy Design for Enhancing the Fracture Resistance of Heat Treated High Pressure Die-Castings

2010 ◽  
Vol 654-656 ◽  
pp. 954-957 ◽  
Author(s):  
Roger N. Lumley ◽  
Maya Gershenzon ◽  
Dayalan R. Gunasegaram
Keyword(s):  
Heat Treatment ◽  
High Pressure ◽  
Fracture Resistance ◽  
Heat Treating ◽  
A380 Alloy ◽  
Conventional Aluminum Alloy ◽  
Heat Treated ◽  
Treatment Technologies ◽  
Die Castings ◽  
Dimensional Instability

Recently, heat treatment technologies have been developed by the CSIRO Light Metals Flagship in Australia that allow the 0.2% proof stress of conventional aluminum alloy high pressure diecastings (HPDC’s) to be more than doubled without encountering problems with blistering or dimensional instability [1,2]. A range of other properties may also be improved such as fatigue resistance, thermal conductivity and fracture resistance. However, the current commercial HPDC Al-Si-Cu alloys have not been developed to exploit heat treatment or to optimize these specific mechanical properties, and one potential limitation of heat treating HPDC’s is that fracture resistance may be reduced as strength is increased. The current paper presents the outcomes of a program aimed at developing highly castable, secondary Al-Si-Cu HPDC alloys which display significantly enhanced ductility and fracture resistance in both the as-cast and heat treated conditions. Kahn-type tear tests were conducted to compare the fracture resistance of the conventional A380 alloy with a selection of the newly developed compositions. A comparison has also been made with the current permanent mold cast aluminium alloys and it is shown that the new HPDC compositions typically display higher levels of both tensile properties and fracture resistance.

scholarly journals Subsurface Microstructural Evolution of High-Pressure Diecast A365: From Cast to Cold-Sprayed and Heat-Treated Conditions

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 432
Author(s):  
Alino Te ◽  
Bryer C. Sousa ◽  
Brajendra Mishra ◽  
Danielle L. Cote
Keyword(s):  
High Pressure ◽  
Surface Modification ◽  
Aluminum Alloy ◽  
Cold Spray ◽  
Spray Deposition ◽  
Cost Effective ◽  
Atomic Diffusion ◽  
Near Surface ◽  
Aluminum Castings ◽  
Heat Treated

The use of cold spray deposition, coupled with diffusion-driven thermal postprocessing, is considered herein as a surface modification process such that near-surface microstructural, micromechanical, and microchemical property improvements can be procured for cost-effective and common aluminum alloy castings. Since the present work was an exploratory investigation into the realm of cold spray induced, high-pressure diecast aluminum subsurface property development and evolution, as well as surface modification, one significant aim was to formalize a set of fundamental observations for continued consideration of such an approach to achieving premium aluminum alloy properties from cost-effective alternatives. Nickel, copper, and titanium cold spray modified near-surface regions of the cost-effective high-pressure diecast A365 system was considered. Near-surface, subsurface, and surface evolution was documented across each of the three pure metal coatings. The analysis was continued across two postprocessing coating-substrate atomic diffusion inspired heat-treated conditions as well. Using energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, optical microscopy, and various insights gleaned from an original contextualization of the relevant cold spray literature, noteworthy results were recorded and discussed herein. When copper feedstock was employed alongside thermal postprocessing, diverse surface-based intermetallic compounds formed alongside exotic diffusion zones and severely oxidized regions, thus eliminating thermally activated copper cold-sprayed consolidations from future work too. However, both nickel and titanium cold spray surface modification processing demonstrated potential and promise if correct processing stages were performed directly and chronologically. Consequently, a platform is presented for further research on cold sprayed surface microstructural and property modification of cost-effective alloyed aluminum castings.

Applications of Squeeze Casting for Automobile Parts

2013 ◽  
Vol 773-774 ◽  
pp. 887-893
Author(s):  
Pongsak Dulyapraphant ◽  
Ekkachai Kittikhewtraweeserd ◽  
Nipon Denmud ◽  
Prarop Kritboonyarit ◽  
Surasak Suranuntchai
Keyword(s):  
High Pressure ◽  
Squeeze Casting ◽  
Die Casting ◽  
Solution Treatment ◽  
Casting Process ◽  
High Pressure Die Casting ◽  
Heat Treated ◽  
Automotive Parts ◽  
Die Casting Process ◽  
Pressure Die Casting

With an increasing pressure on automotive weight reduction, the demand on the lighter weight automotive components continues to increase. In recent years, squeeze casting processes have been used with different aluminium alloys to produce high integrity automotive parts. In this study, the indirect squeeze casting processes is adopted to cast a motorcycles component originally produced by a high pressure die casting process using aluminium alloy ADC12. To minimize amount of gas porosity inside squeeze casts, concepts of (1) minimization of ingate velocity along with (2) bottom filling pattern during the die filling, and (3) maximization of intensifications casting pressure are applied. Then parts are casted with both conventional high pressure die casting and indirect squeeze casting processes. Comparative evaluation of mechanical properties was made between HPDC casts and squeeze casts both in as-cast and heat treated conditions. Results from the experiment have shown that squeeze casts can pass the blister test at 490 °C for 2.5 hours. Then, squeeze casts are heat treated by solution treatment at 484 °C for 20 minutes and artificial age at 190 °C for 2.5 hours, respectively. This improves UTS of the heat treated squeeze cast to 254.14 MPa with 1.84% of elongation, while the UTS of as cast condition from both processes is not significantly different.

The Formation Process of the Microstructure of Al2O3-Al3Ti-Al In-Situ Composite

1997 ◽  
Vol 3 (S2) ◽  
pp. 727-728
Author(s):  
H.H. Luo ◽  
D.Z. Wang ◽  
H.X. Peng ◽  
Cheng Liu ◽  
C.K. Yao
Keyword(s):  
Squeeze Casting ◽  
Volume Fraction ◽  
Average Diameter ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Al Composite ◽  
Heat Treated ◽  
Intermetallic Matrix Composites ◽  
Processing Techniques

In the last decade, new in-situ processing techniques, such as DIMOX™, XD™, VLS and SHS, for fabricating metal and intermetallic matrix composites have emerged. It is expected that the in-situ formed composites may reveal not only excellent dispersion of fine reinforcing particles, but high thermodynamical stability and high temperature performance. The fully dense Al2O3-Al3Ti-57Vol%Al composite was in-situ processed by combing combustion synthesis with squeeze casting utilizing the reaction between TiO2 powder (with average diameter of 0.6μm and volume fraction of 14%) and pure Al (99.5%). First, the 14Vol%TiO2/Al bulk materials were fabricated via squeeze casting method, subsequently, the TiO2/Al materials were heat treated to form final in-situ composites. Using XRD, SEM, TEM and HRTEM techniques, the microstructure and its evolution were investigated.The X-ray diffraction pattern of the composite is shown in Fig.1 which indicates that the composite is composed of A12O3, Al3Ti and Al. According to the reaction formula between TiO2 and Al the volume fraction of Al in the composite is about 57%. Fig.2 is a typical scanning electron micrograph of the composite.

Vanadium Additions to a High-Cr White Iron and its Effects on the Abrasive Wear Behavior.

MRS Advances ◽  
2020 ◽  
Vol 5 (59-60) ◽  
pp. 3077-3089
Author(s):  
Alexeis Sánchez ◽  
Arnoldo Bedolla-Jacuinde ◽  
Francisco V. Guerra ◽  
I. Mejía
Keyword(s):  
Heat Treatment ◽  
Abrasive Wear ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Wear Behaviour ◽  
White Iron ◽  
Heat Treated ◽  
Bulk Hardness ◽  
Abrasive Wear Behavior ◽  
Vanadium Carbides

AbstractFrom the present study, vanadium additions up to 6.4% were added to a 14%Cr-3%C white iron, and the effect on the microstructure, hardness and abrasive wear were analysed. The experimental irons were melted in an open induction furnace and cast into sand moulds to obtain bars of 18, 25, and 37 mm thickness. The alloys were characterized by optical and electronic microscopy, and X-ray diffraction. Bulk hardness was measured in the as-cast conditions and after a destabilization heat treatment at 900°C for 45 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 a load of 60 N for 1500 m. The results show that, vanadium additions caused a decrease in the carbon content in the alloy and that some carbon is also consumed by forming primary vanadium carbides; thus, decreasing the eutectic M7C3 carbide volume fraction (CVF) from 30% for the base iron to 20% for the iron with 6.4%V;but overall CVF content (M7C3 + VC) is constant at 30%. Wear behaviour was better for the heat-treated alloys and mainly for the 6.4%V iron. Such a behaviour is discussed in terms of the CVF, the amount of vanadium carbides, the amount of martensite/austenite in matrix and the amount of secondary carbides precipitated during the destabilization heat treatment.

scholarly journals Mechanochemical Synthesis and Nitrogenation of the Nd1.1Fe10CoTi Alloy for Permanent Magnet

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3854
Author(s):  
Hugo Martínez Sánchez ◽  
George Hadjipanayis ◽  
Germán Antonio Pérez Alcázar ◽  
Ligia Edith Zamora Alfonso ◽  
Juan Sebastián Trujillo Hernández
Keyword(s):  
Mechanochemical Synthesis ◽  
Applied Field ◽  
Volume Fraction ◽  
Synthesis Method ◽  
High Energy ◽  
Direction Parallel ◽  
Best Value ◽  
Heat Treated ◽  
Bcc Phase ◽  
First Time

In this work, the mechanochemical synthesis method was used for the first time to produce powders of the nanocrystalline Nd1.1Fe10CoTi compound from Nd2O3, Fe2O3, Co and TiO2. High-energy-milled powders were heat treated at 1000 °C for 10 min to obtain the ThMn12-type structure. Volume fraction of the 1:12 phase was found to be as high as 95.7% with 4.3% of a bcc phase also present. The nitrogenation process of the sample was carried out at 350 °C during 3, 6, 9 and 12 h using a static pressure of 80 kPa of N2. The magnetic properties Mr, µ0Hc, and (BH)max were enhanced after nitrogenation, despite finding some residual nitrogen-free 1:12 phase. The magnetic values of a nitrogenated sample after 3 h were Mr = 75 Am2 kg–1, µ0Hc = 0.500 T and (BH)max = 58 kJ·m–3. Samples were aligned under an applied field of 2 T after washing and were measured in a direction parallel to the applied field. The best value of (BH)max~114 kJ·m–3 was obtained for 3 h and the highest µ0Hc = 0.518 T for 6 h nitrogenation. SEM characterization revealed that the particles have a mean particle size around 360 nm and a rounded shape.

scholarly journals Phase Stability of Iron Nitride Fe4N at High Pressure—Pressure-Dependent Evolution of Phase Equilibria in the Fe–N System

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3963
Author(s):  
Marius Holger Wetzel ◽  
Tina Trixy Rabending ◽  
Martin Friák ◽  
Monika Všianská ◽  
Mojmír Šob ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Equilibria ◽  
Phase Stability ◽  
Polymorphic Transition ◽  
Ex Situ ◽  
Stable Phase ◽  
Iron Nitride ◽  
Phase System ◽  
Target Composition ◽  
Heat Treated

Although the general instability of the iron nitride γ′-Fe4N with respect to other phases at high pressure is well established, the actual type of phase transitions and equilibrium conditions of their occurrence are, as of yet, poorly investigated. In the present study, samples of γ′-Fe4N and mixtures of α Fe and γ′-Fe4N powders have been heat-treated at temperatures between 250 and 1000 °C and pressures between 2 and 8 GPa in a multi-anvil press, in order to investigate phase equilibria involving the γ′ phase. Samples heat-treated at high-pressure conditions, were quenched, subsequently decompressed, and then analysed ex situ. Microstructure analysis is used to derive implications on the phase transformations during the heat treatments. Further, it is confirmed that the Fe–N phases in the target composition range are quenchable. Thus, phase proportions and chemical composition of the phases, determined from ex situ X-ray diffraction data, allowed conclusions about the phase equilibria at high-pressure conditions. Further, evidence for the low-temperature eutectoid decomposition γ′→α+ε′ is presented for the first time. From the observed equilibria, a P–T projection of the univariant equilibria in the Fe-rich portion of the Fe–N system is derived, which features a quadruple point at 5 GPa and 375 °C, above which γ′-Fe4N is thermodynamically unstable. The experimental work is supplemented by ab initio calculations in order to discuss the relative phase stability and energy landscape in the Fe–N system, from the ground state to conditions accessible in the multi-anvil experiments. It is concluded that γ′-Fe4N, which is unstable with respect to other phases at 0 K (at any pressure), has to be entropically stabilised in order to occur as stable phase system. In view of the frequently reported metastable retention of the γ′ phase during room temperature compression experiments, energetic and kinetic aspects of the polymorphic transition γ′⇌ε′ are discussed.

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