Microstructural and Cold Workability Assessment of a New ODS Ferritic Steel

A new ODS composition (Fe-14Cr-2W-0.3Ti-0.3Y2O3) developed in the ExtreMat integrated Project has been produced by mechanical alloying techniques and consolidated by hot extrusion. This study summarizes some results of characterization and cold workability tests carried out at CEA and EPFL. It appears that the microstructure is fine and uniform after hot extrusion. According to microprobe analysis, solute elements are homogenously distributed in the matrix. However, the relatively high hardness level measured after hot extrusion and heat treatment may be detrimental in case of additional cold processing which is required to produce final shape like thin plates or cladding tubes. An assessment of the cold workability and the effect of the degree of cold work by rolling on recrystallisation temperature are addressed here. It is found that this material can be successfully cold rolled with a high degree of cold work (up to 60% of thickness reduction) without any damage. According to optical micrographs and Differential Scanning Calorimetry (DSC) measurements, it seems that the recrystallisation temperature remains always very high (above 1400°C) even though cold work level increases (up to 66% of thickness reduction). However, the hardness values begin to decrease for heat treatment temperatures above 1200°C for hot worked conditions and below 1000°C for cold worked conditions, respectively.

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Effect of heat treatment on morphology and dielectric properties of PE cable insulation material

Proceedings of the Nordic Insulation Symposium ◽

10.5324/nordis.v0i24.2284 ◽

2017 ◽

Author(s):

Hossein Ghorbani ◽

Tanbhir Hoq ◽

Hans Edin

Keyword(s):

Heat Treatment ◽

Dielectric Properties ◽

Electric Fields ◽

Dielectric Spectroscopy ◽

Sample Thickness ◽

Insulation Material ◽

Scanning Calorimetry ◽

Conduction Current ◽

Dsc Measurements ◽

High Electric Fields

It is known that the heat treatment process in the production of extruded cables, affects the electrical properties of polymeric insulation materials; this effect is via two main phenomena; first, it leads to diffusion and removal of polar substances from the system; second, it affects the polymer morphology by increasing the polymer chain relaxation and creation of crystallites, hence increasing the crystallinity of the material. In this study, thick pressed samples with additive free low density polyethylene (LDPE) insulation material were heat treated at different conditions for different periods of times. Differential scanning calorimetry (DSC) measurements confirmed that heat treatment leads to higher crystallinity and higher lamella thickness in LDPE. Dielectric properties of the material was studied by conduction current measurement and dielectric spectroscopy. Conduction current of samples with different heat treatment times was measured at high electric fields which shows that the conduction current of LDPE is affected by heat treatment. Generally, the apparent conductivity decreases by heat treatment. Dielectric spectroscopy measurements show that heat treatment does not have a significant effect on real and imaginary permittivity of the polymer. Interestingly, an increase in the sample thickness via heat treatment, was observed both by sample thickness related to the memory effects in the polymer which needs to be taken into consideration for accurate capacitance measurements.

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Effects of Hafnium, Heat Treatment and Cycling under an- Applied Stress on The Transformations of Cold Worked Niti-Based Shape Memory Alloys

MRS Proceedings ◽

10.1557/proc-481-237 ◽

1997 ◽

Vol 481 ◽

Author(s):

Chen Zhan ◽

Ralph H. Zee ◽

Paul E. Thoma ◽

John J. Boehm

Keyword(s):

Heat Treatment ◽

Shape Memory Alloys ◽

Thermal Cycling ◽

Shape Memory ◽

Cold Work ◽

Tensile Load ◽

Axial Tensile ◽

Heat Treated ◽

Cold Worked ◽

Reduction In Area

ABSTRACTThe effect of thermal cycling under a constant tensile load on the transformation temperatures (TTs) of NiTi-based shape memory alloys (SMAs) is investigated. Three SMAs are examined in this study: a near equiatomic binary Ni49Ti51 alloy and two ternary Ni49Ti51-xHfx alloys with 1 at% and 3 at% Hf. The SMAs are in the form of wires with 40% cold work (reduction in area) and heat treated between 300°C and 600°C. These SMA wires are thermally cycled between their martensite (M) and austenite (A) phases for 100 cycles under an axial tensile stress of 206.8MPa (30Ksi) in air. Results show that the effect of thermal cycling on the M and A TTs depends on heat treatment (HT) temperature and composition in a complex manner. For example, the M TT, of the binary NiTi SMA heat treated between 300°C and 450°C, increases during thermal cycling. However, with HT temperatures between 500°C and 600°C, the M TIT decreases slightly during thermal cycling. For the NiTi-based SMAs that contain 1 at% and 3 at% Hf, the M TT increases during thermal cycling for HT temperatures up to 500°C, and the M TT decreases during thermal cycling when heat treated at 600°C. These results are due to changes in internal stress and structure, such as dislocation density and arrangement, which are affected by HT temperature and thermal cycling. The influence of Hf content on the changes in the M and A TTs during thermal cycling is also shown.

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The Effects of Cold Work and Heat Treatment on the Properties of Nitinol Wire

ASME 2007 2nd Frontiers in Biomedical Devices ◽

10.1115/biomed2007-38012 ◽

2007 ◽

Cited By ~ 6

Author(s):

Masao Drexel ◽

Guna Selvaduray ◽

Alan Pelton

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Tensile Testing ◽

Cold Work ◽

Precipitation Strengthening ◽

Thermally Activated ◽

Nitinol Wire ◽

Good Biocompatibility ◽

Cold Worked ◽

Engineering Alloys

Shape memory and superelastic capabilities coupled with good biocompatibility give Nitinol the ability to provide functionality seldom possible with traditional engineering alloys. In this study the effect of heat treatments of 300 ∼ 550°C for 2 ∼ 180 minutes on Ti-50.8%Ni (at.%) wire of 30% and 50% cold work was investigated. Transformational and mechanical properties were characterized through the bend and free recovery (BFR) method and tensile testing. Thermally activated precipitation and annealing processes occurred. Annealing processes tended to increase the slope and the total strain recovery of the BFR plots. Two TTT diagrams were constructed illustrating the trends in the Austenite Finish Temperature (Af) of the wires. A maximum precipitation rate occurred at approximately 450°C. Precipitation strengthening was evident in both 30% and 50% cold-worked wires. However, only in the former did an increase in UTS occur. Recrystallization began at approximately 450°C for both wires.

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Characterization of NiTi Shape Memory Wires by Differential Scanning Calorimetry and Transmission X-ray Diffraction

MRS Proceedings ◽

10.1557/proc-246-225 ◽

1991 ◽

Vol 246 ◽

Author(s):

Ming-Yuan Kao ◽

Sepehr Fariabi ◽

Paul E. Thoma ◽

Husnu Ozkan ◽

Louis Cartz

Keyword(s):

Heat Treatment ◽

Differential Scanning Calorimetry ◽

Heat Treatment Temperature ◽

Room Temperature ◽

Cold Work ◽

Treatment Temperature ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Niti Wires

AbstractThe reversible transformations between the Austenite (A) and Martensite (M) phases of NITI shape memory wires having a 78°C austenlte finish temperature (950°C annealed) were studied In the cold work and heat treatment ranges between 14 to 62% and 400 to 525°C respectively. The ranges of peak Transformation Temperatures (TI), determined by Differential Scanning Calorimetry (DSC) at a 10°C/min rate, were found to be 56 to 75°C, -28 to 33°C, and 38 to 52°C for the respective high temperature A, low temperature M, and the Intermediate Rhombohedral (R) phases. The degree of cold work and heat treatment had significant effects on the TT of NITI wires. The peak TT of A and M decreases with Increasing cold work. Except for the 14% cold worked wires, the peak TT Increases with Increasing heat treatment temperature for M, and Increases with Increasing heat treatment temperature for A for temperatures higher than 450°C. The peak IT of R Increases with Increasing cold work and decreasing heat treat temperature.Using MoKα radiation, transmission x-ray diffraction analysis was utilized to determine the phases at room temperature on wires thinned down to 0.05 to 0.01 mm in diameter. The diffraction patterns of body-centered cubic austenite (132) and monodlinic martenslte (B19) for NITi were both Identified. In addition, extra diffraction lines observed for various samples were tentatively assigned to M and the Intermediate R-phase. Depending on the thermal history and the processing conditions, the NITI wires consist of either a pure M, a mixture of A and R, or a mixture of A, R, and M at room temperature.

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The Influence of Hafnium Content, Cold Work, and Heat Treatment on the R-Phase Transformation of Niti Based Shape Memory Alloys

MRS Proceedings ◽

10.1557/proc-459-281 ◽

1996 ◽

Vol 459 ◽

Author(s):

Chen Zhang ◽

Paul E. Thoma ◽

Ralph H. Zee

Keyword(s):

Heat Treatment ◽

Differential Scanning Calorimetry ◽

Phase Transformation ◽

Shape Memory Alloy ◽

Shape Memory Alloys ◽

Shape Memory ◽

Cold Work ◽

Niti Shape Memory Alloy ◽

Scanning Calorimetry ◽

Complex Manner

ABSTRACTThe R-phase transformation of a Ti-rich NiTi shape memory alloy (SMA) and two ternary SMAs having the compositions Ni49Ti51-XHfx with lat% and 3at% Hf, has been investigated. The influence of cold work (CW) and heat treatment (HT) on the R-phase transformation is analyzed thermally using Differential Scanning Calorimetry (DSC). Results show that the R-phase transformation depends on the SMA composition as well as the CW and HT conditions in a complex manner. For example, the formation of R-phase upon cooling from austenite (A) is increasingly suppressed with the substitution of Hf for Ti. For the ternary SMA with 3at% Hf, the A→R and R→A transformations are observed only at relatively large amounts of CW (above approximately 40%) and at a high HT temperature (450°C). DSC results also show that for the Ti-rich NiTi and the ternary SMA containing lat% Hf, the A→R and R→A transformation temperatures (TTs) are insensitive to cold work at a HT temperature of 450°C. However, at a lower HT temperature of 350°C, the TTs are found to decrease with increasing CW. For a given CW, the A→R and R→A transformations decrease with decreasing HT temperature and the effect is greatest at high CW (>50%) conditions. An effort is made to identify the factors responsible for the observed behavior in the R-phase transformation.

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ALMANITE W

Alloy Digest ◽

10.31399/asm.ad.ci0042 ◽

1974 ◽

Vol 23 (3) ◽

Keyword(s):

Heat Treatment ◽

Fracture Toughness ◽

Impact Strength ◽

Surface Treatment ◽

High Hardness ◽

Heat Treating ◽

Austenitic Matrix ◽

Matrix Type ◽

Martensitic Matrix ◽

Cast Condition

Abstract ALMANITE W comprises a series of three types of austenitic-martensitic white irons characterized by high hardness and relatively good impact strength. Type W1 has a pearlitic matrix. Type W2 has a martensitic matrix, Type W4 is highly alloyed to provide an austenitic matrix in the as-cast condition which may be further modified to give a martensitic matrix by heat treatment or by refrigeration. This datasheet provides information on composition, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-42. Producer or source: Meehanite Metal Corporation.

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TELNIC BRONZE

Alloy Digest ◽

10.31399/asm.ad.cu0004 ◽

1953 ◽

Vol 2 (1) ◽

Keyword(s):

Heat Treatment ◽

Corrosion Resistance ◽

Physical Properties ◽

Base Alloy ◽

Cold Work ◽

High Strength ◽

Heat Treating ◽

Hot Workability ◽

Copper Base ◽

Copper Base Alloy

Abstract Chase TELNIC BRONZE is a high strength copper-base alloy, hardenable both by heat treatment and cold work, and also having good conductivity, corrosion resistance, cold and hot workability, and excellent machinability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: Cu-4. Producer or source: Chase Brass & Copper Company Inc..

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CYCLOPS 62

Alloy Digest ◽

10.31399/asm.ad.ts0181 ◽

1966 ◽

Vol 15 (8) ◽

Keyword(s):

Fracture Toughness ◽

Physical Properties ◽

Tensile Properties ◽

Tool Steel ◽

Cold Work ◽

High Hardness ◽

Heat Treating ◽

High Tempering

Abstract Cyclops 62 is an air-hardening tool steel with exceptional resistance to softening when tempering. It is recommended for cold work applications where high hardness after high tempering temperatures is a requirement. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, and joining. Filing Code: TS-181. Producer or source: Cyclops Corporation.

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CPM REX 25

Alloy Digest ◽

10.31399/asm.ad.ts0365 ◽

1980 ◽

Vol 29 (7) ◽

Keyword(s):

Heat Treatment ◽

High Speed ◽

High Speed Steel ◽

High Hardness ◽

Heat Treating ◽

High Speeds ◽

Aisi Type ◽

Tool Performance ◽

End Mills ◽

Machining Operations

Abstract CPM REX 25 is a super high-speed steel made without cobalt. It is comparable to AISI Type T15 cobalt-containing high-speed steel in response to heat treatment, properties, and tool performance. CPM REX 25 is recommended for machining operations requiring heavy cuts, high speeds and feeds, and difficult-to-machine materials of high hardness and abrasion resistance. Typical applications are boring tools, drills, gear cutters, punches, form tools, end mills and broaches. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-365. Producer or source: Crucible Materials Corporation.

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CYCLOPS SCK

Alloy Digest ◽

10.31399/asm.ad.ts0346 ◽

1979 ◽

Vol 28 (3) ◽

Keyword(s):

Heat Treatment ◽

Wear Resistance ◽

Physical Properties ◽

Tool Steel ◽

Cold Work ◽

Heat Treating ◽

Optimum Combination ◽

Cold Work Tool Steel ◽

Minimum Distortion

Abstract CYCLOPS SCK is a cold-work tool steel with a balanced composition to provide air hardening and an optimum combination of toughness, wear resistance and minimum distortion during heat treatment. Typical applications are shear blades, trimming dies and forming rolls, including grade rolls for cutlery and flatware. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, and machining. Filing Code: TS-346. Producer or source: Cyclops Corporation.

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