scholarly journals Mechanisms of near-surface structural evolution in nanocrystalline materials during sliding contact

2017 ◽  
Vol 1 (4) ◽  
Author(s):  
Zhiliang Pan ◽  
Timothy J. Rupert
Keyword(s):  
Nanocrystalline Materials ◽  
Structural Evolution ◽  
Sliding Contact ◽  
Near Surface

scholarly journals Structural Evolution of Near-Surface Layers in NiTi Alloy Caused by an Ion Implantation

2011 ◽  
Vol 120 (1) ◽  
pp. 75-78 ◽  
Author(s):  
Z. Swiatek ◽  
M. Michalec ◽  
N. Levintant-Zayonts ◽  
J. Bonarski ◽  
A. Budziak ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Niti Alloy ◽  
Structural Evolution ◽  
Surface Layers ◽  
Near Surface

A Surface Analytical Study of the Effects of Water and Oxygen on Tribological Behavior of DLC Films

2005 ◽  
Author(s):  
O. L. Eryilmaz ◽  
A. Erdemir ◽  
J. A. Johnson ◽  
N. Mehta ◽  
B. Prorok
Keyword(s):  
Surface Chemistry ◽  
Friction And Wear ◽  
Analytical Study ◽  
Tribological Behavior ◽  
Mechanistic Explanation ◽  
Sliding Contact ◽  
Diamond Like Carbon ◽  
Near Surface ◽  
X Ray ◽  
Contact Surfaces

In this study, we explored the effects of water and oxygen molecules on friction and wear of diamond-like carbon (DLC) films. Specifically, using Raman and x-ray photoelectron spectroscopies we attempted to analyze the near surface chemistry and microstructure of sliding contact surfaces and correlated these findings with changes in friction and wear of DLC films. Tribological tests were run in a ball-on-disk machine under 2 to 5 N loads and in dry and moist nitrogen and oxygen environments. Based on the tribological and surface analytical findings, a mechanistic explanation is provided for the high friction and wear of DLC in dry and humid oxygen environments.

Scuffing mechanism of near-surface material during lubricated severe sliding contact

Wear ◽  
2011 ◽  
Vol 271 (9-10) ◽  
pp. 1750-1753 ◽  
Author(s):  
O.O. Ajayi ◽  
C. Lorenzo-Martin ◽  
R.A. Erck ◽  
G.R. Fenske
Keyword(s):  
Sliding Contact ◽  
Surface Material ◽  
Near Surface

scholarly journals Rolling and Rolling-Sliding Contact Fatigue Failure Mechanisms in 32 CrMoV 13 Nitrided Steel—An Experimental Study

2021 ◽  
Vol 11 (21) ◽  
pp. 10499
Author(s):  
Luís Coelho ◽  
António C. Batista ◽  
João Paulo Nobre ◽  
Maria José Marques
Keyword(s):  
Residual Stress ◽  
Fatigue Failure ◽  
Failure Mechanisms ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Sliding Contact ◽  
Surface Layers ◽  
Near Surface ◽  
Nitrided Steel ◽  
Inclined Cracks

The aim of this work is to characterize the rolling and rolling-sliding contact fatigue failure mechanisms on the 32CrMoV13 nitrided steel. During rolling contact fatigue tests (RCF), two general features were observed: specimens presenting short lives and rough and sharpened spalling damage and specimens presenting long lives and only microspalling marks. It was possible to determine a contact fatigue limit of 3 GPa. During rolling-sliding contact fatigue tests (RSCF), a clearly different behaviour between the two specimens in contact has been observed: the driver shows circumferential and inclined cracks and only inclined cracks appear in the follower. This behaviour can be understood if the effect of the residual stress state in near-surface layers is considered. Before RCF tests, the residual stresses are compressive in all near-surface layers. After RCF tests, strong residual stress relaxation and even reversing behaviour was observed in the axial direction, which facilitates the surface crack initiation in the circumferential direction at rolling track borders.

scholarly journals Depth to Magnetic Sources Using Spectral Analysis of High Resolution Aeromagnetic Data Over Machina and Environs, Northeastern Nigeria

2019 ◽  
Vol 11 (1) ◽  
pp. 70
Author(s):  
Hamza Maina Sadiq ◽  
Alhaji Adam Zarma
Keyword(s):  
High Resolution ◽  
Geothermal Energy ◽  
Structural Evolution ◽  
Magnetic Intensity ◽  
Aeromagnetic Data ◽  
Linear Features ◽  
Acid Rock ◽  
Near Surface ◽  
The North ◽  
Hydrocarbon Maturation

Analysis of high resolution aeromagnetic data over Machina and its environment shows areas of low total magnetic intensity contour values are hosts to thicker overburden sediments and near surface intrusive rock bodies reside over high total magnetic intensity contour regions. Positive and negative residual anomaly values depict the presence of basic and acid rock units; however, the acid rocks dominate over the basic components. Major linear features of the residual anomaly are oriented along the NE – SW direction. Some linear features however, cross cut the major lineaments along the NW – SE, N –S, and E – W directions. A NW – SE cross section of the residual anomaly shows irregularity of the bedrock floor. The negative residual anomalies are underlain by granite rocks, while the positive values are within the domain of basic intrusive. Determination of the magnetic source depth revealed depths to the top of the deeper and the shallower sources ranging from 0.6 – 2.0 km and from 0.4 - 0.9 km respectively. Thicker sedimentary covers are underlain by basement rocks while; shallower magnetic horizons are composed of intrusive igneous bodies. Maximum sedimentary thickness of 2.0 km in the study area might not be adequate enough for hydrocarbon maturation and accumulation. Segment directional histogram data shown on rose diagram exhibits strike directions along the E – W, NE – SW, NW – SE, NNE – SSW and NNE – SSW. Most of the fracture lines dip at angles lower than 10 degrees. The north dipping direction group of lineaments is prevalent. Orientations of the structural elements are in conformity with the dominant regional structural grain of the country. Cross- cutting of the lineaments may be related to the geothermal energy in the area as higher interconnected lineaments are associated with higher geothermal energy. Rugged terrain reliefs might have resulted from the effects of tectonic and structural evolution in the area. Variability of the dip angles is associated with non-uniform framework of the forces of deformation on the rocks and/or differential responses of the rocks to the stress imposed on them.

Prediction Model of Surface Topography Evolution Due to Micropitting

2005 ◽  
Author(s):  
P. Wang ◽  
D. Y. Hua ◽  
T. G. Keith
Keyword(s):  
Prediction Model ◽  
Surface Topography ◽  
Contact Stresses ◽  
Sliding Contact ◽  
Asperity Contact ◽  
Surface Material ◽  
Near Surface ◽  
Surface Asperity ◽  
Surface Finishes ◽  
Modification Of The Surface

Micropitting is often observed on hardened materials that are involved with rolling/sliding contact. Even though micropitting is not a catastrophic failure, it may lead to excessive wear or macroscopic pitting. Field experiences and lab testing results have demonstrated that micropitting has a strong correlation to surface topography. Surface asperity contact induces elevated stresses that in turn cause near surface material distress. In this study a micropitting prediction model, based on the contact stresses of rough surfaces, is proposed. Surface topography is modified due to micropitting. The modification of the surface topography causes a redistribution of the contact stresses. Consequently, the intervention between surface topography and the stress field may form a course of surface degradation, or the contact surface may reach steady state without generating any further micropits. The evolution of surface topography is demonstrated for different surface finishes. The comparative micropitting wear volumes and depths are summarized for these finishes.

scholarly journals Depth to Magnetic Sources Using Spectral Analysis of High Resolution Aeromagnetic Data over Machina and Environs, Northeastern Nigeria

2019 ◽  
Vol 2 (2) ◽  
Keyword(s):  
High Resolution ◽  
Geothermal Energy ◽  
Structural Evolution ◽  
Magnetic Intensity ◽  
Aeromagnetic Data ◽  
Linear Features ◽  
Acid Rock ◽  
Near Surface ◽  
The North ◽  
Hydrocarbon Maturation

Analysis of high resolution aeromagnetic data over Machina and its environment shows areas of low total magnetic intensity contour values are hosts to thicker overburden sediments and near surface intrusive rock bodies reside over high total magnetic intensity contour regions. Positive and negative residual anomaly values depict the presence of basic and acid rock units; however, the acid rocks dominate over the basic components. Major linear features of the residual anomaly are oriented along the NE-SW direction. Some linear features however, cross cut the major lineaments along the NW-SE, N-S, and E-W directions. A NW-SE cross section of the residual anomaly shows irregularity of the bed rock floor. The negative residual anomalies are underlain by granite rocks, while the positive values are within the domain of basic intrusive. Determination of the magnetic source depth revealed depths to the top of the deeper and the shallower sources ranging from 0.6-2.0 km and from 0.4-0.9 km respectively. Thicker sedimentary covers are underlain by basement rocks while; shallower magnetic horizons are composed of intrusive igneous bodies. Maximum sedimentary thickness of 2.0 km in the study area might not be adequate enough for hydrocarbon maturation and accumulation. Segment directional histogram data shown on rose diagram exhibits strike directions along the E-W, NE-SW, NW-SE, NNE-SSW and NNE-SSW. Most of the fracture lines dip at angles lower than 10 degrees. The north dipping direction group of lineaments is prevalent. Orientations of the structural elements are in conformity with the dominant regional structural grain of the country. Cross- cutting of the lineaments may be related to the geothermal energy in the area as higher interconnected lineaments are associated with higher geothermal energy. Rugged terrain reliefs might have resulted from the effects of tectonic and structural evolution in the area. Variability of the dip angles is associated with non-uniform framework of the forces of deformation on the rocks and/or differential responses of the rocks to the stress imposed on them.

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