E. Hajduczek

Fabrication Technologies of the Sintered Materials Including Materials for Medical and Dental Application

This chapter of the book presents the basis of classical powder metallurgy technolo‐ gies and discusses powder fabrication, preparation, preliminary moulding, sintering and finish treatment operations. A general description of the materials and products manufactured with the classical powder metallurgy methods is presented. New variants are characterised along with special and hybrid technologies finding their applications in powder metallurgy. Special attention was drawn to microporous titanium and to TiAl6V4 alloy fabricated using hybrid rapid manufacturing technologies with selective laser sintering/selective laser melting (SLS/SLM) used for innovative implant scaffolds in medicine and regenerative dentistry. Laser deposition, thermal spraying and detonation spraying of powders are also discussed as special methods in which powders of metals and other materials are used as raw materials.

Composite Materials Infiltrated by Aluminium Alloys Based on Porous Skeletons from Alumina, Mullite and Titanium Produced by Powder Metallurgy Techniques

The infiltration technology with reinforcement in the form of porous skeletons fabricated with powder metallurgy methods has been presented in relation to the general characteristics of metal alloy matrix composite materials. The results of our own investigations are presented pertaining to four alternative technologies of fabrication of porous, sintered skeletons, and their structure and their key technological properties are presented. Porous skeletons made of Al2O3 aluminium are sintered reactively using blowing agents or are manufactured by ceramic injection moulding (CIM) from powder. Porous skeletons made of 3Al2O3⋅2SiO2 mullite are achieved by sintering a mixture of halloysite nanotubes together with agents forming an open structure of pores. Titanium porous skeletons are achieved by selective laser sintering (SLS). The structure and properties of composite materials with an aluminium alloy matrix—mainly EN ACAlSi12 and also EN AC-AlSi7Mg0.3 alloys—reinforced with the so manufactured skeletons are also described. A unique structure of the achieved composite materials, together with good mechanical properties and abrasive wear resistance at low density, ensured by an aluminium alloy matrix, are indicating broad application possibilities of such composites.

Laser modification of hot-work tool steels gradient layers P551

The objective of the present work was to study the modification of the microstructure of hot-work tool steels X40CrMoV5-1 and X38CrMoV5-3 during the surface modifying by means of laser technology. The aim of such treatment was to harden and alloy the steel surface which had been previously coated with tungsten carbide (WC) and were introduced using the rotor conveyer to improve the properties of the surface layer. Development of the surface layer was observed in which one can distinguish the remelted zone, heat-affected zone and the transient zone. The fine grained, dendritic structure occurs in the remelted and alloyed zone with the crystallization direction connected with the dynamical heat abstraction from the laser beam influence zone.The fine grained martensite structure is responsible for hardness increase of the alloyed layer. It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.The objective of the present work was to study the modification of the microstructure of hot-work tool steels X40CrMoV5-1 and X38CrMoV5-3 during the surface modifying by means of laser technology. The aim of such treatment was to harden and alloy the steel surface which had been previously coated with tungsten carbide (WC) and were introduced using the rotor conveyer to improve the properties of the surface layer. Development of the surface layer was observed in which one can distinguish the remelted zone, heat-affected zone and the transient zone. The fine grained, dendritic structure occurs in the remelted and alloyed zone with the crystallization direction connected with the dynamical heat abstraction from the laser beam influence zone.The fine grained martensite structure is responsible for hardness increase of the alloyed layer. It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the ...

Laser alloyed hot-work tool steels with WC carbides

Investigations include alloying the X40CrMoV5-1 hot-work tool steel surface layer with the tungsten carbide, using the high power diode laser (HPDL). The structural mechanism was determined of surface layers development, effect was studied of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer, and especially on its hardness, abrasive wear resistance, and roughness. The remelted zone structure is characterized by the significant martensite dispersion with its lathes length several times shorter than of those developed during the conventional quenching. Martensite twining occurs in some locations, retained austenite, and very fine precipitations of the M6C and M7C3 type carbides are observed as broken network on dendrite boundaries, as well as the high-dispersive ones inside of certain grains. The fine grained martensite structure is responsible for hardness increase of the alloyed layer. It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.Investigations include alloying the X40CrMoV5-1 hot-work tool steel surface layer with the tungsten carbide, using the high power diode laser (HPDL). The structural mechanism was determined of surface layers development, effect was studied of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer, and especially on its hardness, abrasive wear resistance, and roughness. The remelted zone structure is characterized by the significant martensite dispersion with its lathes length several times shorter than of those developed during the conventional quenching. Martensite twining occurs in some locations, retained austenite, and very fine precipitations of the M6C and M7C3 type carbides are observed as broken network on dendrite boundaries, as well as the high-dispersive ones inside of certain grains. The fine grained martensite structure is responsible for hardne...