FEATURES OF THERMAL EXPANSION OF HIGH-STRENGTH INVAR ALLOYS

Invar alloys with both high strength and low thermal expansion are urgently needed in fields such as overhead power transmission, aero-molds, and so on. In this paper, Cr was introduced as a cost-efficient alloying element into the Fe-36Ni binary invar alloy to increase its mechanical strength. Our results confirmed that fine Cr7C3 precipitants, together with some Fe3C, in the invar alloy aged at 425 °C could be obtained with a short aging time. Those precipitants then grew and aggregated at grain or sub-grain boundaries with an increase in aging time. Simultaneously, mechanical strength and coefficient of thermal expansion (CTE) parabolically varied with the increase in aging time. The sample aged at 425 °C for 7 h presented a maximum strength of 644.4 MPa, together with a minimum coefficient of thermal expansion of 3.30 × 10−6 K−1 in the temperature range of 20–100 °C. This optimized result should be primarily attributed to the precipitation of the nanoscaled Cr7C3.

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DELTALLOY 4032

Alloy Digest ◽

10.31399/asm.ad.al0347 ◽

1998 ◽

Vol 47 (4) ◽

Keyword(s):

Wear Resistance ◽

Thermal Expansion ◽

Physical Properties ◽

Surface Treatment ◽

Tensile Properties ◽

Surface Finish ◽

Coefficient Of Thermal Expansion ◽

Single Point ◽

High Strength ◽

Corrosion And Wear

Abstract Deltalloy 4032 has good machinability and drilling characteristics when using single-point or multispindle screw machines and an excellent surface finish using polycrystalline or carbide tooling. The alloy demonstrates superior wear resistance and may eliminate the need for hard coat anodizing. Deltalloy 4032 is characterized by high strength and a low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion and wear resistance as well as machining and surface treatment. Filing Code: AL-347. Producer or source: ALCOA Wire, Rod & Bar Division.

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Thermal Property Evaluation of Chilled Aluminum-Alumina MMC

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1101.79 ◽

2015 ◽

Vol 1101 ◽

pp. 79-82

Author(s):

B.C. Suresh ◽

S.B. Arun

Keyword(s):

Thermal Expansion ◽

Composite Materials ◽

Thermal Property ◽

Coefficient Of Thermal Expansion ◽

Matrix Material ◽

High Strength ◽

Stir Casting ◽

Al Alloy ◽

Industrial Growth ◽

Property Evaluation

Now a day’s composite materials are taking very important role in industrial growth. Composite materials are widely used in Automobiles, aerospace, submarine and also in other major fields, due to their special characteristics like light weight, high strength, stiffness, corrosion resistance. The determination of Coefficient of Thermal Expansion (CTE) of MMCs is important to aid its usage in high temperature environment as in the case of automobile combustion chamber. In these applications the stability of the composites over a long period of operation is a critical design considerationPresent work deals with the thermal property evaluation of the Al alloy / alumina metal matrix composite developed using the Stir Casting with chilling route technique. LM 26 Al alloy is being selected as the matrix material as it is a potential alloy for automotive piston applications. Al alloy / alumina MMCs was cast under end chilling technique by dispersing the reinforcement from 6 to 12 wt% the steps of 3% to study the variation in its thermal properties. At the same time chill material is also changed (Copper and MS) for different composition of MMCs cast to study the thermal behavior variations. After casting the required MMC, test specimens were prepared as per the standards to conduct thermal conductivity (K) tests and coefficient of thermal expansion (CTE) tests. Above tests were repeated for different composites containing different weight % of dispersed cast using different chills.

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Description of the PM Process by Using Ishikawa-Analysis

Materials Science Forum ◽

10.4028/www.scientific.net/msf.752.48 ◽

2013 ◽

Vol 752 ◽

pp. 48-56

Author(s):

Andrea Simon ◽

Károly Kovács ◽

C. Hakan Gür ◽

Tadeusz Pieczonka ◽

Zoltán Gácsi

Keyword(s):

Thermal Conductivity ◽

Thermal Expansion ◽

Powder Metallurgy ◽

Thermal Expansion Coefficient ◽

Expansion Coefficient ◽

High Strength ◽

Manufacturing Technology ◽

Low Density ◽

Composite Manufacturing ◽

Low Thermal Expansion

Composites are special material which can provide individual properties such as high strength with low density or good thermal conductivity with low thermal expansion coefficient. Composites conform to the constantly evolving and more complex expectations. In order to make a product with good quality, it is important to choose suitable materials and technology. In this research powder metallurgy (PM), as one of the most common composite manufacturing technology, was examined -which factors and mechanisms influence mostly the properties of the product. Ishikawa method was used to reveal these correlations.

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Low-Temperature Sintering of High-Strength β-Eucryptite Ceramics with Low Thermal Expansion Using Li2O-GeO2 as a Sintering Additive

Journal of the American Ceramic Society ◽

10.1111/j.1551-2916.2010.04279.x ◽

2011 ◽

Vol 94 (5) ◽

pp. 1427-1433 ◽

Cited By ~ 16

Author(s):

Toshio Ogiwara ◽

Yoshimasa Noda ◽

Kazuo Shoji ◽

Osamu Kimura

Keyword(s):

Thermal Expansion ◽

Low Temperature ◽

High Strength ◽

Low Temperature Sintering ◽

Sintering Additive ◽

Low Thermal Expansion

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Impact of Cooling Character on Structure and CTE of Invar Alloy with 0.6%C

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.265.807 ◽

2017 ◽

Vol 265 ◽

pp. 807-810

Author(s):

A.S. Zhilin ◽

S.V. Grachev ◽

S.M. Nikiforova

Keyword(s):

Thermal Expansion ◽

Cooling Rate ◽

Coefficient Of Thermal Expansion ◽

Invar Alloy ◽

Cooling Rates ◽

Volume Percentage ◽

Invar Alloys

Metallography analysis of invar alloys crystallized with different cooling rates has been carried out. The study has demonstrated that velocity of crystallization has an impact on the dispersity of graphite. The higher velocity of cooling, the more dispersive graphite is. The volume percentage of graphite in alloy, crystallized with high cooling rate, is lower than compared with low cooling rate. Crystallization with low cooling rate leads to the reduction of the amount of carbon into γ-phase. The coefficient of thermal expansion is basically depends on the amount of carbon into γ-phase.

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Effect of Mo doping on the microstructure and properties of an Fe36Ni Invar alloy

International Journal of Modern Physics B ◽

10.1142/s0217979220502975 ◽

2020 ◽

Vol 34 (31) ◽

pp. 2050297

Author(s):

Liming Dong ◽

Zhaopeng Yu ◽

Xianjun Hu ◽

Fang Feng

Keyword(s):

Grain Size ◽

Thermal Expansion ◽

Grain Boundaries ◽

Coefficient Of Thermal Expansion ◽

Solution Temperature ◽

Microstructure And Properties ◽

Invar Alloys ◽

Average Grain Size ◽

Mo Content ◽

Hot Rolled

The effects of doping with different Mo contents on the microstructure and properties of Fe36Ni Invar alloys were investigated. The results show that when 0.9 wt.% Mo and 1.8 wt.% Mo were added to Fe36Ni, the tensile strengths of the hot rolled alloys were 46 and 61 MPa higher than that of the 0 wt.% Mo sample, respectively. With an increase in Mo content from 0.9 to 1.8 wt.%, the solution temperature of the highest hardness after heat treatment increased from 800[Formula: see text]C to 850[Formula: see text]C, respectively. The addition of 0.9 wt.% Mo refined the average grain size from 37 to 15 [Formula: see text]m, and an excessive amount of Mo (1.8 wt.%) did not refine the grains further. After Mo was added, the precipitates on the original grain boundaries changed into nanoprecipitates dispersed in the grain boundaries and inside the grains. Mo was present in the alloy in the form of a carbide and in solid solution, which affected the magnetic lattice effect and increased the thermal expansion coefficient of the alloy. However, upon comparing the samples doped with 0 wt.% Mo, 0.9 wt.% Mo and 1.8 wt.% Mo, it was found that the addition of 0.9 wt.% Mo not only refined the grain size and improved the mechanical properties of the alloy but also led to a low coefficient of thermal expansion (CTE) over the range from 20[Formula: see text]C to 300[Formula: see text]C.

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Study of the Influence of Refractories Structure on the Thermomechanical Properties of Tunnel Kiln Equipment Lining

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.299.150 ◽

2020 ◽

Vol 299 ◽

pp. 150-156

Author(s):

Tatiana M. Lonzinger ◽

Vadim A. Skotnikov ◽

Alexey M. Sukharev

Keyword(s):

Thermal Expansion ◽

Thermal Stresses ◽

Linear Thermal Expansion ◽

High Strength ◽

Thermomechanical Properties ◽

Petrographic Analysis ◽

Entire Area ◽

Thermal Expansion Coefficients ◽

Concrete Blocks ◽

Tensile Thermal Stress

A study of the influence of refractories’ structure on the thermomechanical properties of the lining of the equipment of tunnel kilns has been carried out. The lining of kiln trolleys is subjected to a mechanical stress distributed evenly over the entire area and the most dangerous to brittle materials, as well as to tensile thermal stresses. The magnitude of the tensile thermal stress depends on the material and the structure of the lining. The mechanisms of destruction of products made of fireclay and liquid concrete have been studied. Mineralogical and petrographic analysis of fireclay refractories have been used, as trolley lining has established metasomatic interaction of the lining with the vapor-gas component of the kiln, as well as with the metal of the trolleys. Monolithic products, made of low-cement concrete with corundum filler, are characterized by high strength and resistance to abrasion. The total value of compression and thermal expansion stresses for them is 3.08 MPa, which is half the value of those of fireclay. When conducting the research to optimize the composition of trolley lining, a technology for manufacturing two-layer concrete blocks, combining the advantages of compositions, based on corundum and fireclay, has been developed. The chemical and granulometric composition of fireclay-based concrete in the lower thermal insulation layer and electrocorundum-based concrete in the upper reinforcing layer were selected in such a way, as to ensure similar values of linear thermal expansion coefficients and prevent possible destruction along the boundary between the layers during the operation.

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Some recent developments in high-strength glasses and ceramics

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1964.0212 ◽

1964 ◽

Vol 282 (1388) ◽

pp. 52-56

Keyword(s):

Thermal Expansion ◽

Bending Strength ◽

Glass Ceramics ◽

High Strength ◽

Fine Grained ◽

Thermal Expansion Coefficients ◽

Low Thermal Expansion ◽

Recent Developments ◽

Expansion Coefficients ◽

Mechanical Strengths

Two areas of development in the field of glasses and ceramics have produced new materials with unusual combinations of properties. Glass-ceramics are melted and formed as glasses by conventional glass-forming techniques, but by a subsequent heat treatment, they are converted to fine-grained crystalline structures with new and useful combinations of properties. Products with thermal expansion coefficients approaching zero and flexural strengths ranging from 10 000 to 50 000 Lb./in. 2 have been made though not all combinations of low thermal expansion coefficients and high mechanical strengths are possible. The second area of development is in so-called Chemcor glasses. Such glass products can be preferentially pre-stressed by chemical means so as to produce an outer layer with high compressive stress and a bending strength in the finished product up to 100 000 Lb/in. 2 .

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