The series of books represents a thorough treatment of ultra-high temperature materials with melting (sublimation or decomposition) points around or over 2500 °C. In the third volume are included physical (structural, thermal, electromagnetic, optical, mechanical, nuclear) and chemical (more than 1100 binary, ternary and multi-component systems, including those used for materials design, data on solid-state diffusion, wettability, interaction with chemicals, gases and aqueous solutions) properties of titanium monocarbide TiC1–x, vanadium monocarbide VC1–x and related 2D-molecular (graphene-like) carbide MXenes, discovered and developed only in the last decade. TiC1–x and VC1–x are also widely applied in the general technological and engineering practice in a wide range of temperatures as parts of highly hard materials (alloys) and special steels. This book will be of interest to researchers, engineers, postgraduate, graduate and undergraduate students alike. For the named materials, readers/users are provided with the full qualitative and quantitative assessment, which is based on the latest updates in the field of fundamental physics, chemistry, nanotechnology, materials science, design and engineering.

http://link.springer.com/content/pdf/10.1007/978-94-024-2039-5.pdf

Ultra-High Temperature Materials III: Refractory Carbides II (Ti and V Carbides)

In this paper, in situ synthesized TiC particles reinforced Fe-based surface composite coatings by multi-pass overlapping gas tungsten arc welding (GTAW) melting process employing a proper amount of graphite and ferrotitanium (FeTi) on AISI 1020 steel substrate was produced. The microstructure and wear properties of the composite coatings were investigated by means of an electron microprobe microanalysis (EPMA), X-ray diffractometer and wear tester. The results showed that the multi-pass overlapping GTAW melting surface composite coatings can be obtained under suitable welding parameters, and no crack and porosity are found in the tracks. The X-ray and EPMA results confirm that TiC particles can be formed via reaction of FeTi and graphite during multi-pass overlapping GTAW melting process. TiC particles present cubic and dendrite shape in the non-overlapping zone. It is found that there occurred TiC particles coarsening at the overlap regions, which can lead to detrimental effects on the hardness and wear performance. Composite coatings give a high hardness and excellent wear resistance; and the wear friction coefficient of the coating is less than that of the 1020 steel. As a result, multi-pass overlapping GTAW melting process can be used effectively for producing surface composite coatings with a pre-placed powder to improve wear resistance of the AISI 1020 steel.

Characterization of in situ synthesized TiC particle reinforced Fe-based composite coatings produced by multi-pass overlapping GTAW melting process

In this paper, the effect of laser cladding process parameters on TiC morphology is studied. Results show that laser parameters play a crucial role in morphology of TiC. Dendritic or spherical TiC particles with different distribution are observed depending on applied laser parameters. Two combined parameters, effective energy and powder deposition density, are used in order to study the effect of laser process parameters on TiC morphology. A series of experiments are conducted in constant laser power and scan speed, constant effective energy and constant powder deposition density in order to study the TiC morphologies. Results show that both combined parameters and laser parameters should be considered in order to interpret the results. Laser parameters have crucial role in establishing the TiC morphologies by means of temperature and chemical composition. Hardness results of the clad zone depend on morphologies and distributions of TiC particles in the clad.

The influence of combined laser parameters on in-situ formed TiC morphology during laser cladding

In the present study, AISI 1045 steel surfaces were alloyed with pre-placed graphite, ferrotitanium and Fe–Cr–B–Si powders by using a tungsten-inert gas (TIG) heat source. The effects of welding parameters and thickness of the pre-placed powder layers on the microstructure and properties of the coatings were also investigated. The results indicated that TiC particles can be obtained by direct metallurgical reaction between ferrotitanium and graphite during the TIG welding process. Most of TiC particles were uniformly distributed in the surface coating. The microhardness showed a gradient variation from the molten boundary to the top surface of the coatings, and it was influenced by the thickness of the pre-placed powder layer and the welding parameters. The surface composite coating exhibited a higher hardness and lower wear rate than that of the substrate due to the formation of TiC carbides.

W. D. Pan

Papers

In-situ synthesis of a TiC-Fe composite in liquid iron

In-situ formation of TiC/Hadfield steel composites