Steels for bearings

The mechanical properties of ex-situ and in-situ metallic glass matrix composites (MGMCs) have proven to be both scientifically unique and of potentially important for practical applications. However, the underlying deformation mechanisms remain to be studied. In this article, we review the development, fabrication, microstructures, and properties of MGMCs, including the room-temperature, cryogenic-temperature, and high-temperature mechanical properties upon quasi-static and dynamic loadings. In parallel, the deformation mechanisms are experimentally and theoretically explored. Moreover, the fatigue, corrosion, and wear behaviors of MGMCs are discussed. Finally, the potential applications and important unresolved issues are identified and discussed.

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Metallic glass matrix composites

https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=2056&context=nanopub

Fatigue Performance Improvement in AISI 4140 Steel by Dynamic Strain Aging and Dynamic Precipitation During Warm Laser Shock Peening

Bulk metallic glasses (BMGs) can exhibit excellent combinations of strength and fracture toughness that cannot be achieved by traditional metals, making them attractive for load bearing, mechanical engineering applications. Furthermore, recent research on BMGs has shown that many early perceived shortcomings, such as apparent brittleness or poor fatigue resistance, are not as big of a problem as once thought. The purpose of this paper is to review some of the unique mechanical characteristics of BMGs along with some of the strategies that may be used to improve or exploit their characteristics so that BMGs may be used as structural materials in engineering applications.

Bulk Metallic Glasses as Structural Materials: A Review

Direct Z-scheme anatase/rutile bi-phase nanocomposite TiO 2 nanofiber photocatalyst with enhanced photocatalytic H 2 -production activity

Cyclic cryogenic pretreatments influencing the mechanical properties of a bulk glassy Zr‐based alloy

https://cyberleninka.org/article/n/736.pdf

Crack Initiation Mechanisms and Threshold Values of Very High Cycle Fatigue Failure of High Strength Steels

High-strength steels have a maximum of the fatigue limit at a certain tensile strength. The decrease of the fatigue limit at still higher tensile strength can be explained by the failure mechanism of high-strength steels which fail due to crack initiation at inclusions or other internal flaws. To increase the fatigue limit two different thermomechanical treatments (TMTs) are applied to the material after classical martensitic hardening and tempering. A TMT results in a decrease of the hardness of about 10%. Different cyclic loading during the TMT can either reduce or increase the fatigue limit. In order to describe and compare the different treatments an evaluation of the stress intensity factors arising at the critical inclusions was carried out. To take into account different numbers of cycles to failure in the calculation a modification of the calculation of the stress intensity factor according to Murakami was successfully developed.

Increasing the fatigue limit of a high-strength bearing steel by thermomechanical treatment

Five well-known Zr-based alloys of the systems Zr–Cu–Al–(Ni–Nb, Ni–Ti, Ag) (Cu = 15.4–36 at.%) with the highest glass-forming ability were comparatively analyzed regarding their pitting corrosion resistance and repassivation ability in a chloride-containing solution. Potentiodynamic polarization measurements were conducted in the neutral 0.01 M Na2SO4 + 0.1 M NaCl electrolyte and local corrosion damages were subsequently investigated with high resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive x-ray spectroscopy (EDX). Both pitting and repassivation potential correlate with the Cu concentration, i.e., those potentials decrease with increasing Cu content. Pit morphology is not composition dependent: while initially hemispherical pits then develop an irregular shape and a porous rim. Corrosion products are rich in Cu, O, and often Cl species. A combination of low Cu and high Nb or Ti contents is most beneficial for a high pitting resistance of Zr-based bulk metallic glasses. The bulk glassy Zr57Cu15.4Al10Ni12.6Nb5 (Vit 106) and Zr52.5Cu17.9Al10Ni14.6Ti5 (Vit 105) alloys exhibit the highest pitting resistance.

/pdf/comparing-the-pitting-corrosion-behavior-of-prominent-zr-59rvsvr5mp.pdf

Eberhard Kerscher

Papers

Cyclic cryogenic pretreatments influencing the mechanical properties of a bulk glassy Zr‐based alloy

Crack Initiation Mechanisms and Threshold Values of Very High Cycle Fatigue Failure of High Strength Steels

Increasing the fatigue limit of a high-strength bearing steel by thermomechanical treatment

Comparing the pitting corrosion behavior of prominent Zr-based bulk metallic glasses

Fatigue behaviour and lifetime calculation of the cast irons EN-GJL-250, EN-GJS-600 and EN-GJV-400