Opening: 00AM - 24PM
Grain size gradient nickel alloys II: Fatigue properties ...

Grain size gradient nickel alloys were tested in a rotating-bending fatigue machine and found to display better fatigue behavior than non-gradient, homogeneous nickel specimens having the same average grain size. This demonstrates that the overall fatigue properties are improved through the concept of a grain size gradient.

Nickel Based Superalloys - Harry Bhadeshia

A superalloy is a metallic alloy which can be used at high temperatures, often in excess of 0.7 of the absolute melting temperature. Creep and oxidation resistance are the prime design criteria. Superalloys can be based on iron, cobalt or nickel, the latter being best suited for aeroengine applications.

[PDF]Get Price
RECRYSTALLIZATION AND GRAIN GROWTH IN NICKEL .

temperature to minimize grain growth. The strain in the parts is fixed by current production practice; therefore, the minimum time and temperature combination that will achieve full recrystallization needs to be determined. 2.1 Nickel-Iron Base Alloy 706 Alloy 706 is a nickel .

[PDF]Get Price
Electroplating Failure Analysis - Finishing

Sep 18, 2008 · Regarding wire bonding. It appears that you are using electroless nickel. High Phosphorus (10% or more) deposits with a small grain size. The high phosphorus interferes with wire bonding. The larger crystallites indicate low phosphorus and better wire bonding. Ultrasonic bonding on nickel requires higher energy than for bonding to copper, gold.

[PDF]Get Price
Grain Size and Its Influence on Materials Properties

Grain size specifics The grain size of carbon and alloy steels is generally understood to mean prior austenitic grain size. On heating steel through its critical range, transforma-tion to austenite takes place. The austenite grains are extremely small when first formed, but grow in size as the time and temper-ature are increased. The grain size ...

Get Price
Grain Boundary-Mediated Plasticity in Nanocrystalline Nickel

Jul 30, 2004 · The plastic behavior of crystalline materials is mainly controlled by the nucleation and motion of lattice dislocations. We report in situ dynamic transmission electron microscope observations of nanocrystalline nickel films with an average grain size of about 10 nanometers, which show that grain boundary–mediated processes have become a prominent deformation mode.

Get Price
Grain Size Comparisons - Copper

Grain Size Comparisons. NOTE: The file size of the Larger and Largest View of the Micrographs are substantially larger than the thumbnail shown.The Larger View images range in size from 11K to 120K depending on the image.The Largest View images range in size from 125K to almost 500K.

[PDF]Get Price
Effect of alloy grain size on the high-temperature ...

The initial grain size of 4 µm was coarsened to a grain size of 65 µm by applying a heat treatment at 1050 °C in inert gas atmosphere for 112 hours. Samples with a dimension of (10 x 10 x 3) mm 3 were used for thermogravimetric study. The samples were ground using SiC paper down to 1200 grid.

  • Published in: Materials Research-ibero-american Journal of Materials · 2005Authors: Vicente Braz Trindade · U Krupp · Behzad Zandi Hanjari · Songlan Yang · Hansjurge.Affiliation: University of SiegenAbout: Grain sizeGet Price
Crystallite - Wikipedia

Reducing grain size is therefore a common way to improve strength, often without any sace in toughness because the smaller grains create more obstacles per unit area of slip plane. This crystallite size-strength relationship is given by the Hall–Petch relationship.

Get Price
Determining Austenite Grain Size of Steels: 4 Methods ...

The grain size is determined in a microscope at a magnification of 100 X by comparing with ASTM standard grain-size charts and the matching number of the grain size is reported. ASTM standard grain size charts have been shown compared with grain size in specimens in Fig. 2.29 to 2.31 or, the microscope may have special eye-piece, which is ...

Get Price
Grain Structure Types - Metallography

GRAlN STRUCTURE TYPES The measurement of grain size, whether by the chart comparison method or by manual or automated measurement methods, is complicated by the different types of grain structures encountered and by the etched appearance of the grains.

Get Price
Metallography of Iron-Nickel Meteorites - vacaero

Jun 05, 2018 · Their size is a function of the phosphorous content. Schreibersite has a variable nickel content, depending upon the temperature at which they nucleated, from about 10 to 50% Ni. The higher nickel content particles tend to be smaller in size and they are more ductile than the larger, lower Ni particles, which are often cracked.

Get Price
Metallography of Superalloys - Vacaero

This is one of several types of duplex grain size conditions that are encountered in superalloys. Large as-forged specimens can also exhibit rather complete (or less complete) grain boundary carbide networks as illustrated in Fig. 5. This structure is from the center of a 305-mm (12-inch) diameter as-forged bar of Alloy 600.

Get Price
Grain boundary strengthening - Wikipedia

Grain-boundary strengthening (or Hall–Petch strengthening) is a method of strengthening materials by changing their average crystallite (grain) size. It is based on the observation that grain boundaries are insurmountable borders for dislocations and that the number of dislocations within a grain have an effect on how stress builds up in the adjacent grain, which will eventually activate ...

Get Price
Effects of Dimensions and Grain Size on Plasticity in the ...

KEYWORDS : Micro -torsion, Nickel wire, Size effects, Plasticity, Grain size effects The structure and grain size effects on the torsional behavior of polycrystalline pure nickel wires with diameters in the range of 0.5 -2 mm are experimentally studied. As a comparison, uniaxial tension testing on wires with the same diameter and grain size ...

Get Price
ASTM and Grain Size Measurements - Metallography

Section B produced E 89-50T, Methods for Estimating the Average Ferrite Grain Size of Low-Carbon Steels, with a chart depicting a ferritic grain structure as revealed by nital etching. This was the first chart (eight pictures) to define grain size in terms of the now familiar ASTM grain size numbers (1 to .

Get Price
Duplex Grain Size in Austenitic and Nickel Based Super ...

Duplex Grain Size in Austenitic and Nickel Based Super-alloys. Metals have a crystalline structure. When a metal solidifies from the molten state, a tude of tiny crystals start to grow. These crystals form the grains in the solid metal. As a wrought metal is formed, the product goes through repeated cycles of rolling to reduce cross ...

Get Price
Determining Austenite Grain Size of Steels: 4 Methods ...

The grain size is determined in a microscope at a magnification of 100 X by comparing with ASTM standard grain-size charts and the matching number of the grain size is reported. ASTM standard grain size charts have been shown compared with grain size in specimens in Fig. 2.29 to 2.31 or, the microscope may have special eye-piece, which is ...

Get Price
How does grain size affect the strength of steel? - Quora

The strength of most metals depends on the average grain size in a polycrystalline material and on the sample size in a monocrystalline materials. To understand this, you need to consider what determines the material strength. The strength of meta...

Get Price
Duplex Grain Size in Austenitic and Nickel Based Super ...

Duplex Grain Size in Austenitic and Nickel Based Super-alloys. Metals have a crystalline structure. When a metal solidifies from the molten state, a tude of tiny crystals start to grow. These crystals form the grains in the solid metal. As a wrought metal is formed, the product goes through repeated cycles of rolling to reduce cross ...

[PDF]Get Price