scholarly journals Wear Protective Effects of Tribolayer Formation for Copper Based Alloys in Sliding Contacts: Alloy Dependent Sliding Surfaces and Their Effects on Wear and Friction

2020 ◽  
Author(s):  
Ulrike Cihak-Bayr ◽  
Robin Jisa ◽  
Friedrich Franek

High sliding wear resistance is generally attributed to high hardness and high mechanical strength. Novel near net shape process technologies such as metal injection moulding (MIM) or lost foam casting (LF) lack forming processes that typically increase strength. Consequently, the materials exhibit large-grained microstructures with low defect densities. Commercial copper alloys (CuSn8, CuNi9Sn6, CuSn12Ni2) well known for good sliding properties were produced using MIM and LF and characterised in the current study. Their wear and friction behaviour was compared to conventionally produced variants in a lubricated, reciprocating sliding test against steel. The results showed an equal or superior wear resistance and lower friction levels for large-grained microstructures evolving in MIM and LF. SEM, FIB and EBSD studies revealed a tribolayer on the surface and a tribologically transformed layer (TTL), composed of a nano-crystalline zone or partially rotated grains, and selective hardening of grains. The extent of the TTL was different for alloys that were chemically identical but exhibited different initial microstructures. Innovative production routes investigated here showed no tribological drawbacks, but present the potential to increase lifetime, as nano-crystalline zones may render the sample more prone to wear. We present a hypothesis on the cause for these behaviours.

1993 ◽  
Vol 330 ◽  
Author(s):  
J-P. Hirvonen ◽  
R. Lappalainen ◽  
J. Koskinen ◽  
J. Likonen ◽  
M. Pekkarinen

ABSTRACTBiological materials such as shells possess a useful combination of mechanical properties. For instance, good fracture toughness combined with a relatively high hardness has been reported. The response of these properties to a tribological performance could presumably be very beneficial. Unfortunately no such research has been reported, although this kind of information is invaluable in possible utilization of biomimetic or biological processes in producing of materials.In this work chemical composition of Unio Crassus shells were characterized using secondary ion mass spectroscopy (SIMS) and Rutherford backscattering spectroscopy (RBS) and the microstructure was determined with X-ray diffraction (XRD) and scanning electron microscopy (SEM). Specimens of 20×10 mm in size with a thickness of a few millimetres were cut and mechanically polished followed by ultrasonic cleaning in deionized water. Wear and friction measurements were performed in a pin-on-disc tester with a hardened steel pin 6 mm in diameter as a counter face. Tests were carried out in a relative humidity of 50 % at room temperature with a sliding speed of 15 mm/s. The measurements indicate a friction coefficient of 0.3 – 0.4 which is reasonable low. Moreover, wear resistance was found to be excellent. The wear resistance of the material was similar to those of the best synthetic diamond-like carbon films. The storage of the specimen at room temperature for 150 days deteriorated the material resulting in much worse tribological properties.


Alloy Digest ◽  
1971 ◽  
Vol 20 (8) ◽  

Abstract REYNOLDS 390 and A390 are hypereutectic aluminum-silicon alloys having excellent wear resistance coupled with good mechanical properties, high hardness, and low coefficients of expansion. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, and machining. Filing Code: Al-203. Producer or source: Reynolds Metals Company.


Alloy Digest ◽  
2009 ◽  
Vol 58 (9) ◽  

Abstract Carpenter ACUBE 100 Alloy is cobalt-base and exhibits corrosion resistance and wear resistance. The alloy was designed as direct replacement of beryllium copper alloys. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion and wear resistance as well as forming, heat treating, and machining. Filing Code: CO-117. Producer or source: Carpenter Specialty Alloys.


Alloy Digest ◽  
1968 ◽  
Vol 17 (10) ◽  

Abstract HOWMET No. 3 is a cobalt-base alloy having high hardness and compressive strength, high heat and corrosion resistance, along with excellent abrasion and wear resistance. It is recommended for bushings, scrapers, valve parts, and other machinery components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Co-56. Producer or source: Howmet Corporation Metal Products Division.


Alloy Digest ◽  
1962 ◽  
Vol 11 (9) ◽  

Abstract DOUBLE SEVEN is an air hardening high-carbon high-chromium tool and die steel having high hardness and wear resistance. It is recommended for shear blades, cold working tools, and heavy duty dies. 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 joining. Filing Code: TS-124. Producer or source: Edgar Allen & Company Ltd, Imperial Steel Works.


Alloy Digest ◽  
2006 ◽  
Vol 55 (3) ◽  

Abstract DuraTech 30 is a superhigh-speed steel evolved from the ASTM M3-2 composition, but with added cobalt. The exotic composition offers improved toughness and very high hardness. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on high temperature performance and wear resistance as well as heat treating, machining, and powder metal forms. Filing Code: TS-629. Producer or source: Timken Latrobe Steel.


2019 ◽  
Vol 813 ◽  
pp. 159-164
Author(s):  
Carlos Alberto Souto ◽  
Gustavo Faria Melo da Silva ◽  
Laura Angelica Ardila Rodriguez ◽  
Aline C. de Oliveira ◽  
Kátia Regina Cardoso

Coatings with high entropy alloys of the AlCoCrFeNiV system were obtained by selective laser melting on low carbon steel substrates. The effect of the variation of the Fe and V contents as well as the laser processing parameters in the development of the coating were evaluated. The coatings were obtained from the simple powder mixtures of the high purity elemental components in a planetary ball mill. The coatings were obtained by using CO2 laser with a power of 100 W, diameter of 0.16 mm, and scan speed varying from 3 to 12 mm/s. Phase constituents, microstructure and hardness were investigated by XRD, SEM, and microhardness tester, respectively. Wear resistance measurements were carried out by the micro-abrasion method using ball-cratering tests. The coatings presented good adhesion to the substrate and high hardness, of the order of 480 to 650 HV. Most homogeneous coating with nominal composition was obtained by using the higher scan speed, 12 mm/s. Vanadium addition increased hardness and gave rise to a high entropy alloy coating composed by BCC solid solutions. Ball cratering tests conducted on HEA layer showing improvement of material wear resistance, when compared to base substrate, decreasing up to 88% its wear rate, from 1.91x10-6 mm3/Nmm to 0.23x10-6 mm3/Nmm.


2021 ◽  
Author(s):  
Mei Yang ◽  
Yishu Zhang ◽  
Haoxing You ◽  
Richard Smith ◽  
Richard D. Sisson

Abstract Selective laser melting (SLM) is an additive manufacturing technique that can be used to make the near-net-shape metal parts. M2 is a high-speed steel widely used in cutting tools, which is due to its high hardness of this steel. Conventionally, the hardening heat treatment process, including quenching and tempering, is conducted to achieve the high hardness for M2 wrought parts. It was debated if the hardening is needed for additively manufactured M2 parts. In the present work, the M2 steel part is fabricated by SLM. It is found that the hardness of as-fabricated M2 SLM parts is much lower than the hardened M2 wrought parts. The characterization was conducted including X-ray diffraction (XRD), optical microscopy, Scanning Electron Microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to investigate the microstructure evolution of as-fabricated, quenched, and tempered M2 SLM part. The M2 wrought part was heat-treated simultaneously with the SLM part for comparison. It was found the hardness of M2 SLM part after heat treatment is increased and comparable to the wrought part. Both quenched and tempered M2 SLM and wrought parts have the same microstructure, while the size of the carbides in the wrought part is larger than that in the SLM part.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2225 ◽  
Author(s):  
Martin Löbel ◽  
Thomas Lindner ◽  
Thomas Lampke

High hardness and good wear resistance have been revealed for the high-entropy alloy (HEA) system AlCoCrFeNiTi, confirming the potential for surface protection applications. Detailed studies to investigate the microstructure and phase formation have been carried out using different production routes. Powder metallurgical technologies allow for much higher flexibility in the customisation of materials compared to casting processes. Particularly, spark plasma sintering (SPS) enables the fast processing of the feedstock, the suppression of grain coarsening and the production of samples with a low porosity. Furthermore, solid lubricants can be incorporated for the improvement of wear resistance and the reduction of the coefficient of friction (COF). This study focuses on the production of AlCoCrFeNiTi composites comprising solid lubricants. Bulk materials with a MoS2 content of up to 15 wt % were produced. The wear resistance and COF were investigated in detail under sliding wear conditions in ball-on-disk tests at room temperature and elevated temperature. At least 10 wt % of MoS2 was required to improve the wear behaviour in both test conditions. Furthermore, the effects of the production route and the content of solid lubricant on microstructure formation and phase composition were investigated. Two major body-centred cubic (bcc) phases were detected in accordance with the feedstock. The formation of additional phases indicated the decomposition of MoS2.


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