Advances in brazing


Book Description

Advanced ceramic-matrix composites (CMCs) outperform traditional ceramics in many ways and have shown potential for demanding applications. Net-shape manufacture of CMC parts is challenging, and many advanced applications demand robust and reliable integration technologies such as brazing. Brazing of CMC/metal joints is reviewed, highlighting scientific issues together with a discussion of some of the challenges that brazing of CMCs presents. Brazing practices for SiC–SiC, C–SiC, C–C, ZrB2-based ultra-high-temperature composites, and oxide, nitride and silicate-based composites are presented. Recent research results on interface microstructure, composition and properties are discussed. Scaling effects, time–temperature–environment dependent thermomechanical properties, design guidelines and life-prediction analyses, and tools for CMC/metal joints to be used in structures constitute future research imperatives.




Advances in brazing


Book Description

Metal–nonmetal brazing is an established joining method used to fabricate products such as hermetic electronic packages, insulators for power generation and turbo-machinery components. Brazing presents opportunities for the materials engineer seeking to utilize recently engineered materials in advanced applications and extreme environments. Three commonly used brazing methods used for joining metals to nonmetals will be discussed: conventional brazing methods that use metallization coatings on the nonmetal surface to be brazed; active brazing methods that eliminate the need for metallization coatings; and direct brazing methods utilizing conventional brazing filler metals to join and seal packages without prior metallization.




Advances in Brazing


Book Description

Brazing processes offer enhanced control, adaptability and cost-efficiency in the joining of materials. Unsurprisingly, this has lead to great interest and investment in the area. Drawing on important research in the field, Advances in brazing provides a clear guide to the principles, materials, methods and key applications of brazing.Part one introduces the fundamentals of brazing, including molten metal wetting processes, strength and margins of safety of brazed joints, and modeling of associated physical phenomena. Part two goes on to consider specific materials, such as super alloys, filler metals for high temperature brazing, diamonds and cubic boron nitride, and varied ceramics and intermetallics. The brazing of carbon-carbon (C/C) composites to metals is also explored before applications of brazing and brazed materials are discussed in part three. Brazing of cutting materials, use of coating techniques, and metal-nonmetal brazing for electrical, packaging and structural applications are reviewed, along with fluxless brazing, the use of glasses and glass ceramics for high temperature applications and nickel-based filler metals for components in contact with drinking water.With its distinguished editor and international team of expert contributors, Advances in brazing is a technical guide for any professionals requiring an understanding of brazing processes, and offers a deeper understanding of the subject to researchers and engineers within the field of joining. - Reviews the advances of brazing processes in joining materials - Discusses the fundamentals of brazing and considers specific materials, including super alloys, filler metals, ceramics and intermetallics - Brazing of cutting materials and structural applications are also discussed




Advances in brazing


Book Description

The phenomena involved in a brazing process constitute a set of very complex spatially distributed, transient physical and chemical processes, influenced by multiple parameters. This has been difficult to model reliably. This chapter offers a high level review of three broad areas of modeling: (i) the heating/cooling process during brazing, (ii) the thermomechanical behavior of brazed assemblies, and (iii) micro-scale phenomena, taking place in the joint zone and primarily related to transport phenomena. This discussion illustrates the importance of modeling brazing processes and its increasing contribution to the long-lasting success of the art.




Advances in brazing


Book Description

The brazing of carbon–carbon (C/C) composites and metals is a necessary manufacturing technique for some high-performance applications. In this chapter, the fundamentals of brazing C/C composites to metals are described including the wettability of the brazing filler on C/C composites and the coefficient of thermal expansion (CTE) difference between C/C composites and metals. Commercially available brazing fillers for the brazing of C/C composites and various metals are listed. The effect of fiber orientation on the joint strength of C/C composites and titanium is described. The manufacturing method for overcoming the mismatch in CTE between C/C composites and metals is also described.




Advances in brazing


Book Description

This chapter investigates the problem of brazing heat-resistant materials – high nickel-base and γ-TiAl-base intermetallic alloys. Diffusion brazing with filler metals of the Ni–Cr–B and Ni–Cr–B–Si systems is inefficient for nickel alloys, while composite filler metals based on these systems yield satisfactory results. When used as an alternative to boron- and silicon-containing filler metals, alloys of the Ni–Cr–Zr systems do not form hard and brittle phases at the interface in the joints. Filler metals based on the Ti–Zr system are best suited for joining γ-TiAl-base intermetallic alloys. Ti–Zr–Fe and Ti–Zr–Mn alloys, which show promise as brazing filler metals are selected, and structures and mechanical properties of the brazed joints are presented.




Advances in brazing


Book Description

A quiet revolution in industry has happened over the last 50 or so years due to the use of diamond and cubic boron nitride (CBN) in many applications. Joining of diamonds to various materials via brazing is very specific compared with conventional brazing due to the unique nature of diamond. This chapter describes the properties of diamond and CBN, and their wetting by and interaction with metals and alloys; factors that affect these interactions; and practical aspects of diamonds and CBN joining. Some properties of brazed joints of diamond and CBN with different metals, as well as cemented carbide inserts, are presented and discussed. Finally, application examples are provided.




Advances in brazing


Book Description

An important brazing application is the production of cutting and machining tools. This chapter provides an overview of brazing alloys for the joining of cutting materials. Process-related problems and solutions are presented and discussed. High strength values can be achieved with the right filler alloy and joint design. Most cemented carbides consist of a hard material such as tungsten carbide and a metallic binder. Due to the high carbide content, wetting and bonding reactions have to be monitored. Addition of active elements can help to induce a wetting reaction. Brazing ceramic cutting materials requires the use of active filler alloys to achieve a wetting reaction. The chapter reviews the alloys required. A joint can be weakened by interfacial effects or mismatches in physical properties. Employing the right filler metal with an adapted brazing process can significantly improve joint quality. Stress calculations based on the finite element method contribute to better joint design with reduced stress levels.




Advances in brazing


Book Description

Ceramics are inorganic non-metallic materials made from natural or synthetic compounds using shaping and high-temperature sintering processes. At present, the poor plasticity and low impact resistance of engineering ceramics have limited their further application. Joining ceramics or composites to metal is challenging because of their chemical dissimilarity and differences in coefficient of thermal expansion. The complexity and high cost of procedures that can overcome these problems limit their application. In this chapter, the difficulties of brazing ceramics and solutions are presented. The brazing of oxide ceramics, nitride ceramics, carbide ceramics and C/C composites is discussed in more detail.




Introduction to Brazing Technology


Book Description

Introduction to Brazing Technology provides practical guidance for the industrial production of an effectively brazed joint. Written in plain language by an active technical consultant with more than 50 years of brazing experience, this clear and concise book:Explains the fundamental concepts of the brazing processCovers all the common heating meth