Friction stir based welding and processing technologies - processes, parameters, microstructures and applications: A review

Friction surfacing—A review

Laser cladding is a process whereby a new layer of material is deposited on a substrate by laser fusion of blown powders or pre-placed powder coatings. Multiple layers can be deposited to form shapes with complex geometry. This manufacturing process has been used for material surface property modification and for the repair and manufacture of three-dimensional components. Laser cladding has attracted extensive research over the past 30 years. Over 2000 research papers have been published in journals and international conferences. Research in laser cladding covers many scientific issues, including processing techniques, physical and chemical properties of deposited materials and clad—substrate interfaces, microstructure and phases, rapid solidification phenomena, modelling and simulation, and systems engineering and applications. This article, focusing on the rapid heating/cooling processes and material response, summarizes the state of the art on two fundamental scientific aspects: rapid solidific...

Laser surface cladding: The state of the art and challenges

A review on laser deposition-additive manufacturing of ceramics and ceramic reinforced metal matrix composites

Microhardness, wear properties and microstructure of Fe-based coatings with various WC contents on H13 hot-working die steel by laser cladding were investigated. Special attention was paid to the effects of various WC contents on the microstructural characterization and wear properties of different coatings by means of optical microscopy (OM) and scanning electron microscopy (SEM). Results indicated that only a small part of the periphery of the WC in the WC-added coatings was melted, and the un-melted WC particles in the coatings acted as a hard reinforcement. Besides, the microhardness in the cladding layer increased with the increment of the mass fraction of WC particles, and presented a gradient distribution along in-depth direction of the coatings. Furthermore, the Fe-based clad coating with WC particles exhibited a higher wear resistance and a lower friction coefficient compared with the substrate and Fe-based clad coating. In addition, the influence mechanism of WC particles on microstructural evolution and wear resistance was also discussed.

Wear properties and microstructural analyses of Fe-based coatings with various WC contents on H13 die steel by laser cladding

Titanium carbide particles reinforced Fe-based surface composite coatings were fabricated by laser cladding using a 5 kW CO2 laser. The microstructure, phase structure and wear properties were investigated by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction, as well as dry sliding wear test. The results showed that TiC carbides were formed via in situ reaction between ferrotitanium and graphite in the molten pool during the laser-clad process. The morphology of TiC is mainly cubic and dendritic form; and the TiC carbides were distributed uniformly in the composite coating. The TiC/matrix interface was found to be free from cracks and deleterious phases. The coatings reinforced by TiC particles revealed higher wear resistance and lower friction coefficient than that of the substrate and FeCrBSi laser-clad coating.

Microstructure and wear properties of TiC/FeCrBSi surface composite coating prepared by laser cladding

A coating rod of 1Cr18Ni9Ti (321) was deposited on the substrate of mild steel 1020 to be able to perform a friction surfacing experiment. The temperature changes of special points on the coating rod were measured using a thermocouple. The results show that the temperature increase rate at the friction interface reached a high level at first. Then the rate decreased to a low level once the friction system became quasi-steady and the temperature became approximately stable near the melting point of the coating rod. The theory of contact melting was used to build the physical model for the quasi-liquid layer. Subsequently, the corresponding calculations were carried out. The computer simulation results are found to be consistent with the experiment results, and as such, the present study demonstrates the feasibility of applying contact melting theory to the study of friction surfacing. Likewise, this study reveals that the material at the top of the coating rod is plastic, and that it behaves as a quasi-liquid in the friction surfacing process. The study establishes the theory basis for the study of the mechanism of friction surfacing, and provides a new method for investigating other friction-welding techniques.

Transferring mechanism of the coating rod in friction surfacing

Fe-based hardfacing alloys containing molybdenum compound have been deposited on AISI 1020 steel substrates by shield manual arc welding (SMAW) process. The effect of Mo on the microstructure and wear resistance of the Fe-based hardfacing alloys were investigated by means of X-ray diffraction, optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis, as well as wear test. The results indicated that cuboidal and rod-type complex carbides were synthesized in the lath martensite matrix. The fraction of carbides in hardfacing layer increased with an increasing of Mo content. The hardfacing layer with good cracking resistance and wear resistance could be obtained when the amounts of Fe–Mo was controlled within a range of 3–4 wt.%. The improvement of hardness and wear resistance of the hardfacing layers attributed to the formation of Mo 2 C carbide and the solution strengthening of Mo.

Effect of molybdenum on the microstructure and wear resistance of Fe-based hardfacing coatings

APPBP2 enhances non-small cell lung cancer proliferation and invasiveness through regulating PPM1D and SPOP

Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.

X.M. Liu

Papers

Microstructure and wear properties of TiC/FeCrBSi surface composite coating prepared by laser cladding

Transferring mechanism of the coating rod in friction surfacing

Effect of molybdenum on the microstructure and wear resistance of Fe-based hardfacing coatings

APPBP2 enhances non-small cell lung cancer proliferation and invasiveness through regulating PPM1D and SPOP

Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing