Material with Novel Compositions and Fine Microstructljres Produced Via the Mixalloy Process

1988 ◽  
Vol 132 ◽  
Author(s):  
Arthur K. Lee ◽  
Luis E. Sanchez-Caldera ◽  
Jung-Hoon Chun ◽  
Nam P. Suh
Keyword(s):  
High Performance ◽  
Liquid Metals ◽  
Solidification Rate ◽  
Copper Alloys ◽  
Fine Microstructure ◽  
The Matrix ◽  
New Processing ◽  
Rapidly Solidified ◽  
Economical Alternative

ABSTRACTA new processing method, the Mixalloy process, has been developed to process alloys with novel microstructures and compositions. In this process, microstructural control is achieved through the use of turbulent mixing of liquid metals in addition to controlling solidification rate and chemical composition. Boride dispersion strengthened copper alloys were produced using the Mixalloy process. Thermally stable and fine (average less than 100 nm) boride dispersoids were formed by in-situ chemical reaction in the copper alloy matrices during mixing. The uniform mixture of the matrix and dispersoids was then rapidly solidified to maintain the fine microstructure. The consolidated material shows exceptional thermal stability and an excellent combination of strength, ductility, and electrical conductivity. Furthermore, the flexibility of the process allows the matrices of these dispersion strengthened coppers to be easily alloyed to fulfill specific needs. The versatility and simplicity of the Mixalloy process provide an economical alternative to other processing means in the manufacturing of high performance alloys such as dispersion strengthened alloys.

scholarly journals In situ regulation of microstructure and microwave-absorbing properties of FeSiAl through HNO3 oxidation

2021 ◽  
Vol 11 (1) ◽  
pp. 147-157
Author(s):  
Yang Guo ◽  
Liwen Zhang ◽  
Haipeng Lu ◽  
Xian Jian
Keyword(s):  
Oxide Layer ◽  
High Performance ◽  
Competitive Growth ◽  
Microwave Absorbing Properties ◽  
Negative Change ◽  
The Matrix ◽  
Strong Adhesion ◽  
Microwave Absorbing ◽  
Minimum Reflection Loss

Abstract Wrapping insulation of coatings is effective for enhancing the microwave-absorbing properties (MAPs) of ferromagnetic absorbents (FMAs). However, the process is still limited by the low bonding strength with the matrix. Herein, an in situ regulation strategy based on the preparation of thin thickness and strong adhesion insulating layers through HNO3 oxidation was developed to address the limitations. The oxidation process of FeSiAl (FSA) powders was carried out by HNO3 following three main steps. First, the original oxide layer first reacted with HNO3 to form Fe3+ and Al3+. Second, the oxide layer composed of Al2O3 and Fe3O4 was preferentially formed due to the negative change in Gibbs free energy. Finally, the oxide and pigment-deposition layers were subjected to competitive growth and dissolution accompanied by the dissolution of Fe and Al atoms. Oxidation time up to 10 min resulted in the formation of a bilayer structure with a thickness of ∼50 nm on the FSA surface, as well as an outer layer crammed of Al(OH)3 and Fe(OH)3, and an inner layer containing mixed Fe2O3, Fe3O4, Al2O3, and SiO2. The MAPs of as-treated FSA achieved minimum reflection loss (RL) of −25.90 dB at 13.36 GHz, as well as absorption bandwidth of 5.61 GHz (RL < −10 dB) at 10.13–15.74 GHz and thickness of 2.5 mm. In sum, the developed route looks promising for the preparation of high-performance FMAs.

scholarly journals In-situ poling and structurization of piezoelectric particulate composites

2017 ◽  
Vol 28 (18) ◽  
pp. 2467-2472 ◽  
Author(s):  
H Khanbareh ◽  
S van der Zwaag ◽  
WA Groen
Keyword(s):  
Lead Zirconate Titanate ◽  
Piezoelectric Properties ◽  
Lead Zirconate ◽  
Particulate Composites ◽  
Processing Route ◽  
The Matrix ◽  
New Processing ◽  
A Chain ◽  
Particle Configuration

Composites of lead zirconate titanate particles in an epoxy matrix are prepared in the form of 0–3 and quasi 1–3 with different ceramic volume contents from 10% to 50%. Two different processing routes are tested. Firstly a conventional dielectrophoretic structuring is used to induce a chain-like particle configuration, followed by curing the matrix and poling at a high temperature and under a high voltage. Secondly a simultaneous combination of dielectrophoresis and poling is applied at room temperature while the polymer is in the liquid state followed by subsequent curing. This new processing route is practiced in an uncured thermoset system while the polymer matrix still possess a relatively high electrical conductivity. Composites with different degrees of alignment are produced by altering the magnitude of the applied electric field. A significant improvement in piezoelectric properties of quasi 1–3 composites can be achieved by a combination of dielectrophoretic alignment of the ceramic particles and poling process. It has been observed that the degree of structuring as well as the functional properties of the in-situ structured and poled composites enhance significantly compared to those of the conventionally manufactured structured composites. Improving the alignment quality enhances the piezoelectric properties of the particulate composites.

A reactive graphene sheet in situ functionalized hyperbranched polyurethane for high performance shape memory material

RSC Advances ◽  
2014 ◽  
Vol 4 (29) ◽  
pp. 15146-15153 ◽  
Author(s):  
Sibdas Singha Mahapatra ◽  
Madeshwaran Sekkarapatti Ramasamy ◽  
Hye Jin Yoo ◽  
Jae Whan Cho
Keyword(s):  
Shape Memory ◽  
Graphene Sheet ◽  
High Performance ◽  
Graphene Sheets ◽  
Shape Memory Material ◽  
Memory Material ◽  
Covalently Bonded ◽  
Hyperbranched Polyurethane ◽  
The Matrix

Covalently bonded graphene sheets with hyperbranched polyurethane were homogeneously dispersed in the matrix appeared as high performance shape memory material.

Spray Forming and Thermal Processing for High Performance Superalloys

2005 ◽  
Vol 475-479 ◽  
pp. 2773-2778 ◽  
Author(s):  
Guo Qing Zhang ◽  
Zhou Li ◽  
Zhong Wu Liu ◽  
Zhi Hui Zhang ◽  
Yifei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Processing ◽  
High Performance ◽  
Deposition Process ◽  
Spray Forming ◽  
Hot Workability ◽  
Forming Technology ◽  
Turbine Disks ◽  
New Processing ◽  
Rapidly Solidified

A unique pilot low-pressure spray forming plant was established and its spray atomisation and deposition process developed to study the new processing methods for high performance materials and to develop spray forming technology suitable for making sound superalloy preforms. The results indicated that high density (>99%) preforms (billets and rings) with little gas pick-ups and with the microstructural features of rapidly solidified superalloys, i.e. refined equiaxed grains and uniform microstructure, could be achieved after the optimisation of the spray atomisation and deposition process. The effects of subsequent thermal processing on the density, microstructure and mechanical properties of the spray formed superalloy were investigated. Compared to the turbine disks and rings made by wrought superalloys, the spray formed superalloys with identical chemistry showed significantly improved metallurgical quality, higher mechanical properties, and better hot workability.

Microstructures, Properties and In Situ Toughening of Rapidly Solidified Al2O3/YSZ Composite Ceramics Prepared by Combustion Synthesis

2008 ◽  
Vol 368-372 ◽  
pp. 771-774 ◽  
Author(s):  
Zhong Min Zhao ◽  
Long Zhang ◽  
Yi Gang Song ◽  
Wei Guo Wang
Keyword(s):  
Combustion Synthesis ◽  
High Performance ◽  
Large Scale ◽  
Large Angle ◽  
High Energy ◽  
Composite Ceramics ◽  
Directionally Solidified ◽  
Pull Out ◽  
Rapidly Solidified

The large-scale Al2O3/YSZ ceramic plates were prepared by combustion synthesis under high gravity, the ceramics were mainly composed of random-oriented rod-shaped grains, and within the rod-shaped grain aligned nano-submicron YSZ fibers were embedded. Compared to the high-performance directionally solidified ceramics, the hardness, flexural strength and fracture toughness of the eutectic ceramics obtained in the experiment increased by 40.7~55.1%, 9.6~26.0% and 172.0~240.0%, respectively. The increase in hardness and strength of the ceramics could be attributed to nano-submicron YSZ fibers and inter-phase spacing and the refinement of the eutectic grains; meanwhile, high-energy, large-angle boundaries between rod-shaped grains could introduce strong toughening mechanisms involving crack-bridging and pull-out of rod-shaped eutectics.

High performance Nanogold™-in situ hybridzation and its use in the detection of hybridized and PCR-amplified microscopical preparations

1996 ◽  
Vol 54 ◽  
pp. 896-897
Author(s):  
G. W. Hacker ◽  
I. Zehbe ◽  
J. Hainfeld ◽  
A.-H. Graf ◽  
C. Hauser-Kronberger ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Messenger Rna ◽  
High Performance ◽  
Detection System ◽  
Direct Methods ◽  
Genetic Alterations ◽  
Chain Reaction ◽  
Protein Encoding ◽  
Polymerase Chain

In situ hybridization (ISH) with biotin-labeled probes is increasingly used in histology, histopathology and molecular biology, to detect genetic nucleic acid sequences of interest, such as viruses, genetic alterations and peptide-/protein-encoding messenger RNA (mRNA). In situ polymerase chain reaction (PCR) (PCR in situ hybridization = PISH) and the new in situ self-sustained sequence replication-based amplification (3SR) method even allow the detection of single copies of DNA or RNA in cytological and histological material. However, there is a number of considerable problems with the in situ PCR methods available today: False positives due to mis-priming of DNA breakdown products contained in several types of cells causing non-specific incorporation of label in direct methods, and re-diffusion artefacts of amplicons into previously negative cells have been observed. To avoid these problems, super-sensitive ISH procedures can be used, and it is well known that the sensitivity and outcome of these methods partially depend on the detection system used.

Morphology of High-Performance Rigid-Rod Polymer Fibers and Molecular Composites

1989 ◽  
Vol 47 ◽  
pp. 338-339
Author(s):  
W.W. Adams ◽  
S. J. Krause
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Liquid Crystalline ◽  
Molecular Level ◽  
Synergistic Effects ◽  
Tensile Modulus ◽  
Commercial Development ◽  
The Matrix ◽  
Molecular Composites ◽  
Rigid Rod

Rigid-rod polymers such as PBO, poly(paraphenylene benzobisoxazole), Figure 1a, are now in commercial development for use as high-performance fibers and for reinforcement at the molecular level in molecular composites. Spinning of liquid crystalline polyphosphoric acid solutions of PBO, followed by washing, drying, and tension heat treatment produces fibers which have the following properties: density of 1.59 g/cm3; tensile strength of 820 kpsi; tensile modulus of 52 Mpsi; compressive strength of 50 kpsi; they are electrically insulating; they do not absorb moisture; and they are insensitive to radiation, including ultraviolet. Since the chain modulus of PBO is estimated to be 730 GPa, the high stiffness also affords the opportunity to reinforce a flexible coil polymer at the molecular level, in analogy to a chopped fiber reinforced composite. The objectives of the molecular composite concept are to eliminate the thermal expansion coefficient mismatch between the fiber and the matrix, as occurs in conventional composites, to eliminate the interface between the fiber and the matrix, and, hopefully, to obtain synergistic effects from the exceptional stiffness of the rigid-rod molecule. These expectations have been confirmed in the case of blending rigid-rod PBZT, poly(paraphenylene benzobisthiazole), Figure 1b, with stiff-chain ABPBI, poly 2,5(6) benzimidazole, Fig. 1c A film with 30% PBZT/70% ABPBI had tensile strength 190 kpsi and tensile modulus of 13 Mpsi when solution spun from a 3% methane sulfonic acid solution into a film. The modulus, as predicted by rule of mixtures, for a film with this composition and with planar isotropic orientation, should be 16 Mpsi. The experimental value is 80% of the theoretical value indicating that the concept of a molecular composite is valid.

Devitrification products of rapidly solidified Ni-Nb amorphous alloys.

1990 ◽  
Vol 48 (4) ◽  
pp. 950-951
Author(s):  
G. A. Bertero ◽  
W.H. Hofmeister ◽  
N.D. Evans ◽  
J.E. Wittig ◽  
R.J. Bayuzick
Keyword(s):  
Electron Microscopy ◽  
Amorphous Structure ◽  
Sulphuric Acid Solution ◽  
X Ray Diffraction ◽  
High Fracture ◽  
Transmission Electron ◽  
Xrd Techniques ◽  
Rapidly Solidified ◽  
Electromagnetically Levitated

Rapid solidification of Ni-Nb alloys promotes the formation of amorphous structure. Preliminary results indicate promising elastic properties and high fracture strength for the metallic glass. Knowledge of the thermal stability of the amorphus alloy and the changes in properties with temperature is therefore of prime importance. In this work rapidly solidified Ni-Nb alloys were analyzed with transmission electron microscopy (TEM) during in-situ heating experiments and after isothermal annealing of bulk samples. Differential thermal analysis (DTA), scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were also used to characterize both the solidification and devitrification sequences.Samples of Ni-44 at.% Nb were electromagnetically levitated, melted, and rapidly solidified by splatquenching between two copper chill plates. The resulting samples were 100 to 200 μm thick discs of 2 to 3 cm diameter. TEM specimens were either ion-milled or alternatively electropolished in a methanol-10% sulphuric acid solution at 20 V and −40°C.

ULTRONZE

Alloy Digest ◽  
1981 ◽  
Vol 30 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Stress Relaxation ◽  
Physical Properties ◽  
Copper Alloy ◽  
High Performance ◽  
Copper Alloys ◽  
Heat Treating ◽  
Bend Strength ◽  
Excellent Corrosion Resistance ◽  
Relaxation Characteristics

Abstract ULTRONZE is a copper alloy also known as Olin Alloy 654. It bridges the gap between standard high-performance copper alloys and beryllium-copper alloys, thus enabling the design of parts with properties previously only attainable with more expensive materials. The alloy has superior stress-relaxation characteristics, good bend performance and excellent corrosion resistance. Among its typical uses are electrical connectors, fuse clips and relay springs. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: Cu-417. Producer or source: Olin Brass.

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