Part 1 Fundamentals of bioceramics: The structure and mechanical properties of bone Fabrication processes for bioceramics The microstructure of bioceramics and its analysis The mechanical properties of bioceramics The design of ceramics for joint replacement Cellular response to bioactive ceramics In vitro evaluation of bone bioactivity Osteoconduction and its evaluation Osteoinduction and its evaluation. Part 2 Types of bioceramics: Alumina ceramics Zirconia ceramics Bioactive glasses Bioactive glass-ceramics Calcium sulphate Tricalcium phosphate-based ceramics Hydroxyapatite Tricalcium phosphate/hydroxyapatite biphasic ceramics Si-substituted hydroxyapatite Calcium phosphate cement Calcium phosphate coatings Titania-based materials Ceramic-polymer composites Dental ceramics Dental glass-ceramics. Part 3 Clinical applications of bioceramics: Clinical application of bioactive glasses Clinical application of bioactive glass-ceramics Clinical application of hydroxyapatite Clinical applications of alumina ceramics in joint replacement Clinical applications of ceramics/polyethylene in joint replacement Tissue engineering using bioceramics.

Bioceramics and their clinical applications

Ultrasonic-assisted friction-stir welding is a new solid-state metal welding technology, based on friction-stir welding, in which weld performance is improved through application of ultrasound during welding. In this study, a model for the temperature field in 1.8 mm 2024 aluminum alloy is built based on computational fluid dynamics and elastic-plastic mechanics theory. Result show the impact of the ultrasound’s vibrations on the temperature field is less obvious at lower welding speeds. However, at higher welding speeds, it can provide the additional heat to keep sufficient welding temperature. The numerical results are compared with optical micrographs in order to validate the numerical models. Good agreement is obtained.

A study of the temperature field during ultrasonic-assisted friction-stir welding

This paper deals with the heat generation in the Al alloy Al2024-T3 plate
 under different rotating speeds and plunge speeds during the plunge stage of
 friction stir welding (FSW). A three-dimensional finite element model (FEM)
 is developed in the commercial code ABAQUS/Explicit using the arbitrary
 Lagrangian-Eulerian formulation, the Johnson-Cook material law and Coulomb’s
 Law of friction. The heat generation in FSW can be divided into two parts:
 frictional heat generated by the tool and heat generated by material
 deformation near the pin and the tool shoulder region. Numerical results
 obtained in this work indicate a more prominent influence from the
 friction-generated heat. The slip rate of the tool relative to the workpiece
 material is related to this portion of heat. The material velocity, on the
 other hand, is related to the heat generated by plastic deformation.
 Increasing the plunging speed of the tool decreases the friction-generated
 heat and increases the amount of deformation-generated heat, while increasing
 the tool rotating speed has the opposite influence on both heat portions.
 Numerical results are compared with the experimental ones, in order to
 validate the numerical model, and a good agreement is obtained.

/pdf/heat-generation-during-plunge-stage-in-friction-stir-welding-397ihx0xmn.pdf

Heat generation during plunge stage in friction stir welding

Numerical simulation of fatigue crack propagation in friction stir welded joint made of Al 2024-T351 alloy

This paper deals with the heat input and maximum temperature developed during
 friction stir welding with different parameters. Aluminium alloy (AA 6061-T6)
 has been used for experimental and numerical analysis. Experimental analysis
 is based on temperature measurements by using infrared camera, whereas
 numerical analysis was based on empirical expressions and finite element
 method. Different types of defects have been observed in respect to different
 levels of heat input.

/pdf/heat-input-effect-of-friction-stir-welding-on-aluminium-1ssdfbvpqs.pdf

Heat input effect of friction stir welding on aluminium alloy AA 6061-T6 welded joint

A coupled thermo-mechanical model was developed to study the temperature
 fields, the plunge force and the plastic deformations of Al alloy 2024-T351
 under different rotating speed: 350, 400 and 450 rpm, during the friction
 stir welding (FSW) process. Three-dimensional FE model has been developed in
 ABAQUS/Explicit using the arbitrary Lagrangian-Eulerian formulation, the
 Johnson-Cook material law and the Coulomb’s Law of friction. Numerical
 results indicate that the maximum temperature in the FSW process is lower
 than the melting point of the welding material. The temperature filed is
 approximately symmetrical along the welding line. A lower plastic strain
 region can be found near the welding tool in the trailing side on the bottom
 surface. With increasing rotation speed, the low plastic strain region is
 reduced. When the rotational speed is increased, the plunge force can be
 reduced. Regions with high equivalent plastic strains are observed which
 correspond to the nugget and the flow arm.

http://www.doiserbia.nb.rs/img/doi/0354-9836/2012%20OnLine-First/0354-98361200012V.pdf

A coupled thermo-mechanical model of friction stir welding

Abstract In this paper, structural and mechanical properties of APS - atmospheric plasma spray coating Al-12Si are presented. The aim of the research was the optimisation of the flow of powder to produce layers with optimal mechanical and structural properties that will be applied to the worn out parts of airplanes. Three groups of samples were produced, by utilising three powder feed rates: 30 g/min, 45 g/min and 60 g/min. Evaluation of layers’ microhardness was done using HV0.3 method and the bond strengthwas determined by testing of tensile strength. Surface morphology of the deposited powder particles was examined on SEM (Scanning Electron Microscope). The microstructure of the coating with the best measured mechanical properties was subsequently examined in etched condition on optical microscope and SEM (in accordance with the standard PN 585005, Pratt & Whitney). Also, fracture morphology of this coating in deposited state was examined using SEM. It was found that powder feed control with atmospheric plasma spraying can produce dense layers of Al-12Si coating with good bond strength.

/pdf/the-influence-of-powder-feed-rate-on-mechanical-properties-2m93c3856i.pdf

The influence of powder feed rate on mechanical properties of atmospheric plasma spray (APS) Al-12Si coating

This paper defines a set of welding parameters for the Friction-Stir Welding (FSW) of two forged panels of the alloy EN AW 7049A in a T652 temper and discusses the plunge stage of FSW using numerical modeling This multi-component aluminum alloy is characterized by high strength, reduced plasticity and poor weldability Observations of the macrostructure and microstructure clearly showed typical zones of a FSW joint and the appropriate grain sizes The finest grains were observed within the nugget, while the coarsest grains are found to be in the HAZ The ultimate tensile strength is 803 % of the parent material A coupled thermo-mechanical model was developed to study the temperature fields and the plunge force of the alloy EN AW 7049A under different rotating speeds, (300, 400 and 500) r/min, during the FSW process of the plunge stage A three-dimensional FE model has been developed in ABAQUS/Explicit using the arbitrary Lagrangian–Eulerian formulation, the Johnson–Cook material law and Coulomb’s Law of Friction Numerical results indicate that the maximum temperature in the FSW process can be increased with an increase in the rotational speed, which can be used to reduce the plunge force

Friction-stir welding of high-strength aluminium alloys and a numerical simulation of the plunge stage vrtilno torno varjenje visokotrdnih aluminijevih zlitin in numeri^na simulacija faze taljenja

Temperature, plastic strain and heat generation during the plunge stage of
 the friction stir welding (FSW) of high-strength aluminium alloys 2024 T3 and
 2024 T351 are considered in this work. The plunging of the tool into the
 material is done at different rotating speeds. A three-dimensional finite
 element (FE) model for thermomechanical simulation is developed. It is based
 on arbitrary Lagrangian-Eulerian formulation, and Johnson-Cook material law
 is used for modelling of material behaviour. From comparison of the numerical
 results for alloys 2024 T3 and 2024 T351, it can be seen that the former has
 more intensive heat generation from the plastic deformation, due to its
 higher strength. Friction heat generation is only slightly different for the
 two alloys. Therefore, temperatures in the working plate are higher in the
 alloy 2024 T3 for the same parameters of the plunge stage. Equivalent plastic
 strain is higher for 2024 T351 alloy, and the highest values are determined
 under the tool shoulder and around the tool pin. For the alloy 2024 T3,
 equivalent plastic strain is the highest in the influence zone of the tool
 pin.

/pdf/analysis-of-the-tool-plunge-in-friction-stir-welding-529qf5yslq.pdf

Analysis of the tool plunge in friction stir welding - comparison of aluminium alloys 2024 T3 and 2024 T351

N. Bajic, Techno-experts d.o.o – Research and Development Center, Serbia, D. Bajic, University of Montenegro, Faculty of Mechanical Engineering, D. Veljic, Techno-experts d.o.o – Research and Development Center, Serbia, M. Rakin, University of Belgrade, Faculty of Technology and Metallurgy, Z. Janjusevic, Institute fot Technology and other mineral raw materials, Belgrade, Serbia This paper analyzes, from the metallurgical aspect, the quality of the new fl ux-cored wire intended for the MAG welding process in function of changes in shielding gas composition and changes in welding parameters. The results of comparative analysis of the microstructure of the weld metal and Heat Aff ected Zone (HAZ) allow drawing conclusions about the feasibility of introducing a new quality fl ux-cored wire in industrial applications.

/pdf/the-advantages-of-using-activated-flux-cored-wire-compared-1rv5mgdn9j.pdf

Darko Veljić

Papers

A coupled thermo-mechanical model of friction stir welding

The influence of powder feed rate on mechanical properties of atmospheric plasma spray (APS) Al-12Si coating

Friction-stir welding of high-strength aluminium alloys and a numerical simulation of the plunge stage vrtilno torno varjenje visokotrdnih aluminijevih zlitin in numeri^na simulacija faze taljenja

Analysis of the tool plunge in friction stir welding - comparison of aluminium alloys 2024 T3 and 2024 T351

The advantages of using activated flux-cored wire compared to solid wire in the MAG welding process from the aspect of metallurgical characteristics