A Study of the Growth Mechanism of Lenticular Carbides in Cyclically Stressed 52100 Steel

1970 ◽  
Vol 92 (1) ◽  
pp. 54-58 ◽  
Author(s):  
S. Borgese
Keyword(s):  
Cell Walls ◽  
Deformation Band ◽  
Cell Structure ◽  
Nucleation And Growth ◽  
Rolling Contact ◽  
Deformation Bands ◽  
Excess Carbon ◽  
Transmission Electron ◽  
Aisi 52100 ◽  
Aisi 52100 Steel

The deformation bands which form in cyclically stressed AISI 52100 steel inner rings (during rolling contact) are studied by transmission electron microscopy. These deformation bands are regions where the temper carbides have dissolved and a well-developed cell structure has formed. Many of the deformation bands are bordered by lenticular-shaped carbides which form after prolonged cyclic stressing. The deformation bands were tempered in the electron microscope and most were found to be free of excess carbon since no precipitation of carbides occurred at normal tempering temperatures. In one specimen there was profuse precipitation of carbides at the cell walls indicating that an excess of free carbon had segregated around dislocations. It is concluded the regions free of excess carbon are due to the nucleation and growth of a lenticular carbide while no lenticular carbide formed at the deformation band which was supersaturated with carbon.

Microstructural Alterations of Rolling—Bearing Steel Undergoing Cyclic Stressing

1966 ◽  
Vol 88 (3) ◽  
pp. 555-565 ◽  
Author(s):  
J. A. Martin ◽  
S. F. Borgese ◽  
A. D. Eberhardt
Keyword(s):  
Shear Stress ◽  
Fatigue Cracking ◽  
Rolling Bearing ◽  
Cyclic Stress ◽  
Bearing Steel ◽  
Rolling Contact ◽  
Microstructural Alterations ◽  
Transmission Electron ◽  
Aisi 52100 ◽  
A Cell

After prolonged cyclic stressing in rolling contact, AISI 52100 bearing steel parts develop extensive regions of microstructural alteration, designated as white etching areas. These are oriented in predictable directions relative to the rolling track. Lenticular carbides are always associated with these areas. Evidence is presented indicating that the boundaries of lenticular carbides constitute planes of weakness which may be preferred planes of fatigue cracking. In the transmission electron microscope the martensitic structure appears gradually transformed into a cell like structure by the action of cyclic stress. The size of crystallites is greatly reduced in this process. The density of microstructural change is found increased with cycling and is distributed in depth along a curve resembling that of the calculated maximum unidirectional shear stress with little or no visible change in the region of maximum orthogonal (alternating) shear stress.

Steel Composition Effects on Grindability and Rolling Contact Fatigue Resistance of Bearing Steels

1985 ◽  
Vol 107 (4) ◽  
pp. 496-500 ◽  
Author(s):  
A. A. Torrance ◽  
R. J. Stokes ◽  
T. D. Howes
Keyword(s):  
Fatigue Resistance ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Steel Rolling ◽  
Aisi 52100 ◽  
Alternative Material ◽  
Aisi 52100 Steel ◽  
The Difference ◽  
Contact Fatigue Resistance

Measurements of the grindability of a bearing quality AISI 1070 steel show that it is far less susceptible to grinding burn than is AISI 52100 steel. Whereas the behavior in this respect of AISI 52100 steel has been shown to correlate well with Malkin’s thermal model, the behavior of the AISI 1070 material did not show such good correlation, even when the difference in thermal conductivity of the two materials was taken into account. It was shown, however, that the more empirically based model of Peters et al. could provide a useful prediction for AISI 1070 steel and subsequently also for the AISI 52100 steel. Rolling contact tests indicate that its fatigue resistance is as good as that of AISI 52100, so it would seem to merit serious consideration as a cheaper alternative material for mass produced bearings.

Influence of Density on the Compressive Properties in Porous Copper Produced by Spacer Method

2007 ◽  
Vol 561-565 ◽  
pp. 1661-1664
Author(s):  
Masataka Hakamada ◽  
Yuuki Asao ◽  
Tetsumune Kuromura ◽  
You Qing Chen ◽  
Hiromu Kusuda ◽  
...  
Keyword(s):  
Relative Density ◽  
Cell Walls ◽  
Deformation Band ◽  
Deformation Mode ◽  
The Other ◽  
Density Range ◽  
Deformation Bands ◽  
Compressive Properties ◽  
Porous Copper ◽  
Macroscopic Deformation

Porous copper specimens with relative densities of 0.22–0.96 were produced by spacer method and their compressive properties were investigated. In the low relative density range (relative density < 0.5–0.6), porous copper showed a density exponent n of 2.3, where n represents the relative density dependence of yield strength. In this range, the bending and buckling of cell walls and the formation of macroscopic deformation bands were observed. On the other hand, porous copper with a higher relative density (0.5–0.6 < relative density < 0.9–1) had an n value of approximately 1, where the dominant deformation mode of cell walls was yielding and no clear deformation band was observed. Also, in the highest relative density range (relative density is very close to 1), the compressive properties degraded markedly with decreasing density, indicating that stress concentration around the minimal pores occurred in this density range.

scholarly journals Rolling Contact Performance of a Ti-Containing MoS2 Coating Operating Under Ambient, Vacuum, and Oil-Lubricated Conditions

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 752 ◽  
Author(s):  
Harpal Singh ◽  
Kalyan C. Mutyala ◽  
Gary L. Doll
Keyword(s):  
Abrasive Wear ◽  
Frictional Heating ◽  
Rolling Contact ◽  
Oil And Grease ◽  
Grease Lubrication ◽  
Aisi 52100 ◽  
Aisi 52100 Steel ◽  
Order Of Magnitude ◽  
Steel Balls ◽  
Mos2 Coating

Solid lubricant molybdenum disulfide (MoS2) coatings have been frequently used to lubricate mechanisms operating in environments where oil and grease lubrication are ineffective. This work evaluated the rolling contact performance of a Titanium-containing MoS2 coating under humid ambient, vacuum, and oil-lubricated conditions. Weibull analyses of L50 lifetimes of AISI 52100 steel balls coated with a Ti-MoS2 coating paired with uncoated M50 steel rods were determined to be 3.7, 14.5, and 158.6 million cycles in ambient, vacuum, and oil-lubricated environments, respectively. In the ambient and vacuum tests, failures were determined to be associated with the onset of abrasive wear rather than fatigue or spalling. The L50 lifetimes of tests performed in those environments were found to depend upon the wear rate of the coatings on the balls. That is, the Ti-MoS2 functioned as a barrier to the onset of abrasive wear between the steel alloys until the coating was sufficiently worn away. Under oil-lubricated (boundary lubrication) conditions, L50 was found to depend on the durability and composition of tribofilms formed in-situ on the surfaces of the uncoated M50 rods. The tribofilms were comprised of mixtures of MoS2 crystallites and amorphous hydrocarbon (a-C:H). The crystalline MoS2 in the tribofilm originated from the amorphous Ti-MoS2 coating and likely underwent a thermodynamic phase transition as a result of the applied Hertz stress and frictional heating in the contact. The a-C:H in the tribofilm probably originated from a catalytic scission of the polyalphaolefin (PAO) molecules caused by the d-band character of the Mo or Ti in the coating. Overall, the Ti-MoS2-coated balls were effective at extending the operational lifetimes of M50 rods under ambient, vacuum, and oil-lubricated conditions by an order of magnitude.

scholarly journals Roughness Effect in Micropitting and Rolling Contact Fatigue of Silicon Nitride

Ceramics ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 135-147 ◽  
Author(s):  
Mohsen Mosleh ◽  
Keron Bradshaw ◽  
Sonya Smith ◽  
John Belk ◽  
Khosro Shirvani
Keyword(s):  
Silicon Nitride ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Roughness Parameter ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Roughness Parameters ◽  
Aisi 52100 ◽  
Aisi 52100 Steel

An experimental analysis of the role of surface roughness parameters on micropitting and the succeeding rolling contact fatigue (RCF) of silicon nitride against AISI 52100 steel under lubricated conditions was performed. In accelerated fatigue tests using a four-ball tester, the arithmetic mean, root mean square, and peak-to-valley roughnesses of silicon nitride surfaces varied, while the roughness of the steel surface was unchanged. The correlation between the fatigue life and roughness parameters for silicon nitride was obtained. The peak-to-valley roughness was the roughness parameter that dominantly affected the RCF life of silicon nitride. The micropitting of surfaces leading to fatigue intensified as the roughness was increased. Extensive micropitting was observed on the rolling track beyond the trailing edge of the spall region in the circumferential direction.

High Cycle Rolling Contact Load Effects on the Microstructure of 50 Rockwell C AISI 52100 Steel

1972 ◽  
Vol 94 (1) ◽  
pp. 1-4 ◽  
Author(s):  
J. Lyman ◽  
A. E. Hall
Keyword(s):  
High Hardness ◽  
Rolling Contact ◽  
Contact Load ◽  
Elastic Behavior ◽  
Experimental Program ◽  
Microstructural Alterations ◽  
Aisi 52100 ◽  
Aisi 52100 Steel ◽  
Load Effects ◽  
Microstructural Effect

An experimental program to determine the effect of cyclic radial rolling contact load on the microstructure of AISI 52100 steel quenched and tempered to 50 Rockwell C hardness is reported. The magnitude of the load was restricted to result in stress conditions that did not exceed the strain energy of distortion theory limit of elastic behavior. Cycling up to 109 cycles produced familiar “white etching” microstructural alterations around stress concentrators such as inclusions, but no microstructural effect related to the mathematical stress field was detected. Research to improve the elastic limit in high hardness-wear resistant steel appears to be needed.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

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