Laser Additive Manufacturing of Titanium-Based Implants

Titanium and its alloys exhibit a unique combination of mechanical, physical properties and corrosion resistance behaviour which makes them desirable for aerospace, industrial, chemical, medical and energy industries. The selective addition of alloying elements to titanium enables a wide range of physical and mechanical properties to be obtained. Ti-based alloys are finding ever-increasing applications in biomaterials due to their excellent mechanical, physical and biological performance. Intense researches are being pursued in the development of new Ti-based alloys with bio-functionalization closer to human bone, owing to their excellent mechanical strength and resilience when compared to alternative biomaterials, such as polymers and ceramics. Several manufacturing techniques are capable of producing porous materials. There is a need to control pore size, shape, orientation and distribution. This work reviews the application of Ti-based alloys in the biomedical industry and also proposes laser additive manufacture process for the manufacture of medical implants.

Laser Surface Processing for Tailoring of Properties by Optimization of Microstructure

Laser surface processing involves modification of surface microstructure and/or composition of the near surface region of a component using a high power laser beam. The advantages of laser surface processing over conventional equilibrium surface processing include rapid processing rate, retention of non-equilibrium microstructure, alloying in liquid state and development of processed zone with superior properties as compared to the same developed by equilibrium processing route. Microstructure plays an important role to control the final properties of the tailored component. In the present contribution, with a brief introduction to laser, and its application, the microstructures developed under optimum conditions by different laser surface processing will be discussed with the corresponding improvement in properties. Finally, a brief review of the future scope of research in laser surface processing will be presented.

Trend and Development in Laser Surface Modification for Enhanced Materials Properties

This article presents a process review of the commonly available laser surface modification techniques for surface property enhancement. This is reinforced with the specific case treatment of research trends in relation to commonly treated materials. The progression from simple surface modification to the production of components with multifunctional characteristics known as functionally graded material is discussed in combination with emerging research focus on the computational simulation of laser surface modification for optimization of process dynamics.

Enhancement of Surface Integrity of Titanium Alloy with Copper by Means of Laser Metal Deposition Process

The laser metal deposition process possesses the combination of metallic powder and laser beam respectively. However, these combinations create an adhesive bonding that permanently solidifies the laser-enhanced-deposited powders. Titanium alloys (Ti6Al4V) Grade 5 have been regarded as the most used alloys for the aerospace applications, due to their lightweight properties and marine application due to their excellent corrosion resistance. The improvements in the surface integrity of the alloy have been achieved successively with the addition of Cu through the use of Ytterbium laser system powered at maximum of 2000 Watts. The motivation for this research work can be attributed to the dilapidation of the surface of titanium alloy, when exposed to marine or sea water for a longer period of time. This chapter provides the surface modification of titanium alloy with the addition of percentage range of Cu within its lattices; and the results obtained from the characterizations conducted on the laser deposited Ti6Al4V/Cu alloys have been improved.

Laser Metal Deposition Process

Laser metal deposition process belongs to the directed energy deposition class of additive manufacturing process that is capable of producing highly complex part directly from the three dimensional (3D) computer aided design file of the component by adding materials layer after layers. Laser metal deposition process is a very important additive manufacturing process and it is the only class of additive manufacturing process that can be used to repair valued component parts which were not repairable in the past. Also because this additive manufacturing process can handle multiple materials simultaneously, it is used to produce part with functionally graded material. Some of the features of the laser metal deposition process are described in this chapter. Some experimental studies on the laser metal deposition of Titanium alloy- composite are also presented.

Laser-Based Manufacturing Processes for Aerospace Applications

In this chapter the latest developments in Laser manufacturing technologies and processes, used in the aerospace industry, are discussed. Current developments in the aerospace industry are characterised by the reduction of manufacturing and exploitation costs. Thus, the need for implementation of advanced manufacturing technologies and processes in the aeronautic industry, offering cost effective products with improved life cycle, is becoming more and more imperative. Lasers can be used in many industrial machining processes for a variety of materials including metals, ceramics, glass, plastics, and composites. Laser beams, used as machining tools, are not accompanied by problems such as tool wear, tool breakage, chatter, machine deflection and mechanically induced material damage, phenomena that are usually associated with traditional machining processes. The effectiveness of Lasers depends on the thermal nature of the machining process. Nevertheless, difficulties arise due to the difference in the thermal properties of the various components.

Computational Dynamics of Laser Alloyed Metallic Materials for Improved Corrosion Performance

Laser alloying is a material processing method which utilizes the high power density available from defocused laser beam to melt both metal coatings and a part of the underlying substrate. Since melting occur solitary at the surface, large temperature gradients exist across the boundary between the melted surface region and underlying solid substrate, which results in rapid self-quenching and re-solidifications. Alloyed powders are deposited in a molten pool of the substrate material to improve the corrosion resistance of the substrate by producing corrosion resistant coatings. A 3D mathematical model is developed to obtain insights on the behaviour of laser melted pools subjected to various process parameters. Simulation with 3D model with different values of various significant processing parameters such as laser power, scanning speed and powder feed rate influences the geometry and dynamics of the melt pool, and cooling rates. It is expected that the melt pool flow, thermal and solidification characteristics will have a profound effect on the microstructure of the solidified region.

Mitigation of Wear Damage by Laser Surface Alloying Technique

Today's increasingly extreme and aggressive production environments require that machine components be made with materials having specific surface properties such as good wear resistance. Unfortunately, nature does not provide such materials, and alloys having these specific properties are usually very expensive and their use drastically increases components and production costs. Moreover, the economic implications of wear, in form of detrimental effects – and waste, are severe. This includes replacement costs, and all downtime costs related to such replacement. Consequently, companies will increasingly need to look to wear reduction as a direct, immediate avenue for maintaining output quotas and for cutting production costs. Laser coating of engineering alloys with wear resistant materials is one efficient and economical means of increasing the wear resistance of these alloys. This work discusses laser coatings for wear prevention. Different wear mechanisms are discussed and the coatings for specific environment are identified. This will provide information for combating wear.

Laser Additive Manufacturing

Laser additive manufacturing is an advanced manufacturing process for making prototypes as well as functional parts directly from the three dimensional (3D) Computer-Aided Design (CAD) model of the part and the parts are built up adding materials layer after layer, until the part is competed. Of all the additive manufacturing process, laser additive manufacturing is more favoured because of the advantages that laser offers. Laser is characterized by collimated linear beam that can be accurately controlled. This chapter brings to light, the various laser additive manufacturing technologies such as: - selective laser sintering and melting, stereolithography and laser metal deposition. Each of these laser additive manufacturing technologies are described with their merits and demerits as well as their areas of applications. Properties of some of the parts produced through these processes are also reviewed in this chapter.