This article describes the methods for determining the flow rate of metal powders. It examines the factors affecting flow rate, apparent density, and angle of repose of metal powders. The article reviews the frictional properties, cohesive strength, frictional properties, tap density, and compressibility of metal powders. It explains the mechanisms of powder segregation. The article provides information on green strength and springback value of rectangular test bar. It concludes with a discussion on the chemical composition of metal powders.

Plastic deformation of one or both metals is required to obtain bonding in cold welding. This article presents a theoretical model, to explain the bond strength, based on metallographic studies and continuum mechanical analysis of the local plastic deformation in the weld interface. It describes the bonding mechanisms, with illustrations. The article discusses the alternative methods of surface preparation and quality control of the weld interface of a cold weld. It concludes with a description of a variety of metal-forming processes suitable for production of cold welds, namely, rolling, indentation, butt welding, extrusion, and shear welding.

Ultrasonic welding (UW), as a solid-state joining process, uses an ultrasonic energy source and pressure to induce oscillating shears between the faying surfaces to produce metallurgical bonds between a wide range of metal sheets and wires. This article reviews the models of the ultrasonic welding with an emphasis on governing equations, material behavior, and heat generation of the process. It discusses the resulting factors, namely, vibration, friction, temperature, and plastic deformation as well as the bonding strength and its mechanism.

Honeycomb-cored sandwich panels increase part stiffness at a lower weight than monolithic composite materials. This article illustrates an area of a honeycomb-cored sandwich structure composite cross section that is viewed using transmitted polarized light. This area shows the differences in the constituents and resin intermingling. The article discusses the factors that govern the honeycomb core movement and honeycomb core crush, with illustrations. Some common tests performed on honeycomb composites to characterize the skin-to-core bond strength are the climbing drum peel and flatwise tensile tests. The article concludes with a description on the reasons for core failure, which are analyzed after these tests.

Babbitting is a process by which relatively soft metals are bonded chemically or mechanically to a stronger shell or stiffener which supports the weight and torsion of a rotating, oscillating, or sliding shaft. This article focuses on workpiece preparation and babbitting methods. Prior to casting, the workpiece must be scrupulously prepared by various cleaning, fluxing, and tinning steps. Babbitting of bearing shells can be accomplished by three methods, namely, static babbitting, centrifugal casting, and metal spray babbitting.

Explosion welding (EXW), also known as explosive bonding, is accomplished by a high-velocity oblique impact between two metals. This article describes the practice of producing an explosive bond/weld and draws on many previous research results in order to explain the mechanisms involved. It provides a schematic illustration of the arrangement used in the parallel gap explosive bonding process. The article discusses several important concepts pertaining to explosive parameters, hydrodynamic flow, jetting, and metal properties. It summarizes the criteria used to model the explosive bonding process. The article describes bond morphology in terms of wave formation, bond microstructure, and bond strength determination.