The major thrust underlying the processing of Fe-based composites has been directed towards improving the wear resistance of steel or castiron by incorporating some reinforcing phase, e.g., carbides, oxides, etc. The present article provides a review on the various synthesis routes of TiC reinforced Fe-based composites, i.e., powder metallurgy, conventional melting and casting, carbothermic reduction, combustion synthesis, aluminothermic reduction, electron beam radiation, laser surface melting, and plasma spray synthesis, highlighting the advantages and disadvantages associated with the different routes of synthesis.

A Review on the various synthesis routes of TiC reinforced ferrous based composites

Laser cladding is an advanced material processing technology that has potential to deposit various materials locally on highly non-planar and complex surfaces. It can be used to refurbish or improve corrosion, wear and other surface related properties of components. The laser cladding of WC–Co using continuous wave (CW) laser has been tried and problems, like—cracks, porosity, poor bonding, partial melting of WC particles in the Co matrix, etc., have been observed. To resolve these issues, the successful laser cladding with alternate binder materials, like—Ni, Fe, Co–Cr, Ni–B–Si, etc., have been reported. In the present study, a pulsed Nd:YAG laser was used to deposit multi-layer overlapped cladding on low carbon steel substrate using dynamic powder blowing technique. Thus, produced laser cladding samples were subjected to various mechanical tests and metallurgical analyses. The results showed that fully dense and crack free clad surfaces of WC–Co with an excellent metallurgical bonding and low dilution were deposited. No melting of WC particles in the Co matrix was observed during the microscopy. The average microhardness at the clad surface was about 1350 HV, while that at substrate was 200 HV. The observed adhesion strength of the WC–Co cladding to the substrate was about 60 MPa.

Cladding of WC–12 Co on low carbon steel using a pulsed Nd:YAG laser

https://uwaterloo.ca/centre-advanced-materials-joining/sites/ca.centre-advanced-materials-joining/files/uploads/files/gerlich_2012_wear_0.pdf

Microstructures and abrasive wear performance of PTAW deposited Ni–WC overlays using different Ni-alloy chemistries

Methods of wear testing for advanced surface coatings and bulk materials

The creation of a wear-resistant surface of metal matrix composite on AA6061 aluminum alloy by laser surface melting of pre-pasted Mo–WC powder was successfully achieved using a 2-kW CW Nd-YAG laser. A high-quality coating without porosity or cracking was obtained. Excellent bonding between the coating and the aluminum alloy substrate was ensured by the strong metallurgical interface. Different ratios of Mo and WC powders were investigated. The chemical composition, microstructure and surface morphology of the clad layer were analyzed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffractometry (XRD). The surface hardness of the Al specimens clad with Mo/WC is increased seven-fold. The samples have been characterized with abrasive pin-on-disc wear tests. The test results show that the composite coating with a WC hard phase has improved abrasive wear resistance when compared with the as-received Al substrate. The wear mechanism of the specimens is discussed based on microscopic observation of the worn surface.

Microstructure and wear properties of laser surface-cladded Mo–WC MMC on AA6061 aluminum alloy

CO2 laser cladding with blown powder presents many advantages: fusion bonding with the substrate with low dilution, metallurgical continuity in the metallic matrix, high solidification rates, ease of automation, and reduced environmental contamination In the present paper, laser cladding experimental results using families of carbides (tungsten and titanium) mixed with metallic alloys are reported As substrates, low alloy construction steel (AISI 4140) (austenitic stainless steel) samples have been utilized, depending on the particular carbide reinforcement application The coating layers obtained have been characterized by metallurgical examination They show low dilution, absence of cracks, and high abrasion resistance The WC samples, obtained with different carbide sizes and percentages, have been characterized with dry sand rubber wheel abrasion tests and the specimen behaviour has been compared with the behaviour of materials used for similar applications The abrasion resistance proved to be better than that of other widely used hardfacing materials and the powder morphology have a non-negligible influence on the tribological properties

D.D. 'Angelo

Papers

Laser deposition of carbide-reinforced coatings