Laser Metal Deposition Process of Metals, Alloys, and Composite Materials

Additive manufacturing process is an advanced manufacturing process that fabricates components through the addition of materials as against the labour and energy intensive manufacturing processes which are based on material removal, or on application of heat and pressure. Laser metal deposition process belongs to a class of additive manufacturing process that can be used to fabricate three dimensional (3D) computer aided design model of the part by adding materials in a layer wise manner. Apart from the fabrication of 3D objects, laser metal deposition process can also be used to repair broken down parts and for the fabrication of parts that are made of composite and functionally graded materials. This important additive manufacturing technology is comprehensively dealt with in this book. This chapter briefly introduced the additive manufacturing (AM) process, the various classes of the AM technologies, laser metal deposition process, and the advantages as well as the limitation of these technologies.

LASER is an acronym termed Light Amplification by Simulated Emission of Radiation. The development of laser has evolved since its inception and its application has spanned every aspect of human Endeavour. Laser is a phenomenon that has revolutionized the human world. The unique properties of laser such as monochromaticity, directionality and coherency, are responsible for its being favoured in all its areas of application. The application areas span from the smallest laser found in the compact disc player to the large laser found in the industries. The brief history of laser and the basic principle of laser generation are presented in this chapter. Properties of laser, different types of laser, laser safety and their areas of applications are explained. The types of laser that are used in material processing are also presented. The laser material interaction and how important these lasers are in material processing and their use in additive manufacturing technologies, a revolutionary manufacturing process, are also presented.

Laser metal deposition process is an advanced manufacturing process that can be used to fabricate three dimensional (3D) parts from the 3D computer aided design (CAD) model of such parts by adding materials in layers. The CAD digital data of the part is used to generate a motion controlled computer program that is used to control the movement of a laser which then trace all profile of the CAD by injecting the material into the laser focal region of the laser, melted and solidify to form a fully dense track through a moving molten pool that is created by the laser. Tracks and layers are stacked in order to produce the entire component of fused metal that represents the desired 3D CAD object. An important characteristics of this manufacturing process apart from creating a 3D object is its ability to repair high valued parts. Aerospace industry in particular has benefited greatly from this important technology. In this chapter, the detailed process description with the various steps involved in the manufacturing process are explained. The solidification process in the laser metal deposition process with the mechanism of microstructural evolution during this process that give materials processed using this technology, unique properties are also explained in detail.

Laser metal deposition process is an important additive manufacturing process that is used to not only fabricate new three dimensional parts but can also be used to repair high valued parts. Laser metal deposition process has also position itself for product remanufacturing because of its capability to add a new part to an old part and with high metallurgical integrity. Processing parameters play an important role in the evolving physical, metallurgical and mechanical properties of the parts produced. The key processing parameters that influence the material properties in laser metal deposition process include: laser power, scanning velocity, powder flow rate, and gas flow rate. Laser metal deposition process is a highly non-linear process. A slight change in the processing parameters can result in a big change in the material properties. There is also a very strong interaction among these processing parameters. These processing parameters are analyzed in this chapter. There influences on the properties of the produced parts are explained. Some of the relevant literatures in this field are also presented.

Laser metal deposition process has evolved over the past two decades and it has provided the needed solution into a number of engineering problems. The capability of this additive manufacturing technology to produce end used parts directly from metals and alloys is one of the attractive features of this manufacturing process. Laser metal deposition process can be used to create parts without the need for expensive and time wasting tooling. This technology helped to build near net shape components simply by adding materials layer after layer using the three dimensional (3D) model data of the part to be built. Laser metal deposition process is a true green manufacturing process that is capable of reducing material and energy wastages, help to reduce component lead time, and can also help to reduce carbon footprint through product remanufacturing capability. Any complex part that is difficult or prohibitive to be fabricated using the conventional manufacturing processes can readily be made using the laser metal deposition process. In this chapter, the use of laser metal deposition process for the processing of metallic materials and alloys are discussed. The current research activities and the future research direction are also presented.

This chapter deals with the fabrication of composites materials consisting of metals and ceramic or metal-metal composite materials. The flexibilities offered by the laser metal deposition process allow the use of more than one material at the same time during the deposition process. This important process makes it possible to fabricate parts with two dissimilar materials which could be difficult to produce with any other manufacturing process. Functionally graded materials can also be produced with laser metal deposition process. A number of composite materials and functionally graded materials produced using the laser metal deposition process has been investigated and reported in the literature. Laser metal deposition process are also used to produce composite coatings and functionally graded material coatings on other material in order to improve the surface property of such base materials. Some of these studies are presented in this chapter. The properties of these laser deposited composite materials and functionally graded materials are also presented.

Laser metal deposition process is an important additive manufacturing process with a number of capabilities such as the ability to fabricate three dimensional (3D) part directly from the 3D computer aided design profile of the part; the ability to repair worn out parts of very high value that were not repairable in the past; and the ability to build a new part on an existing part that are metallurgically bonded to the old part. This important capability of the laser metal deposition process (ability to add new part on an existing part) is what has positioned this important additive manufacturing process in product remanufacturing and this is a unique laser metal deposition capability. Product remanufacturing is an important aspect of manufacturing that helped to improve material life cycle and helped to reduce scrap. In this chapter, repair, remanufacturing and surface modification applications areas of laser metal deposition process are presented.

Laser metal deposition process, an additive manufacturing process offer lots of advantages such as ability to produce three dimensional (3D) object from the 3D computer aided design of the object- meaning that whatever can be drawn using any CAD software can be manufactured; the ability to make part with composite and functionally graded materials- because it can make use of multi materials at the same time; and the ability to build a new materials on an old material with good metallurgical integrity. These important characteristics of the laser metal deposition process have made it the manufacturing technology of the future. This chapter presents case studies on laser metal deposition of titanium alloy-Ti6Al4V and its composite materials because of the role this materials play in key industrial applications. Also, laser metal deposition process is a relatively new technology and some of the process physics are yet to be fully understood. These case studies shed more lights on the use of this additive manufacturing process for Ti6Al4V and its composites, the influence of some processing parameters on the evolving properties and how such processing parameters can be controlled in order to tailor the properties of the component being fabricated.

Laser metal deposition process is an additive manufacturing technologies that utilize laser as its source of energy to fuse and melt materials together layer after layer to produce three dimensional solid part. Laser metal deposition process has gain a lot of popularities in the research community since its inception because of the exciting properties of the power source ‘laser’ and because of the great potential of the process. Laser delivers heat energy in a coherent manner and with low divergence thereby making the intensity of the laser beam to be very high and can be controlled as required thereby concentrating all the intensity at a point of interest. Laser metal deposition process the capability to produce novel product that maybe difficult if not impossible to fabricate using the conventional subtractive manufacturing processes. Laser metal deposition process can help to extend the service life of parts through the innovative repair process. A number of industries have benefited from these exciting technologies which include: aerospace, automobile, medicine and jewelry. This technology is fairly new and it is a promising technology that may change the way machines are produced. The focus of this chapter is to analyze the progress in this important additive manufacturing technology in term of research efforts in this area and the current state of these technology.

This book presents the laser metal deposition process, and advanced manufacturing process that belongs to a class of additive manufacturing technologies for the production of metals alloys and composite materials. The additive manufacturing technology was introduced and the brief background of the laser metal deposition process was also reviewed. The important energy source used in the laser metal deposition process is laser and it offers a number of capabilities that makes this manufacturing process to leave up what is expected. The laser was also reviewed in Chap. 2 of the book to bring to understanding of the reader and to know how important laser is in the laser metal deposition process. The processing parameters are of great importance in the laser metal deposition process and are also analyzed in this book. Areas of applications, case study and research advancement in laser metal deposition process are also presented. This chapter presents the future research direction in the field of laser metal deposition process and the chapter ends with the summary of the book.