Microstructure and Mechanical Properties of an Al – Mg – Mn – Zr – Sc – B4C Deformable Composite Material

Metal Science and Heat Treatment - Mechanical stirring of particles into a melt is used to obtain a composite material based on alloy Al – 3.5% Mg – 0.4% Mn – 0.15% Zr –...     

Formation of Structure in Clad Abrasion-Resistant Alloys of the Fe – Cr – C – Mo – Ni – Ti – B System Under the Effect of Ultrafine Particles of Titanium Nitride

Metal Science and Heat Treatment - The behavior of the structure of abrasion-resistant alloys of the Fe – Cr – C – Mo – Ni – Ti – B system during electric arc...     

Warm Deformation of Alloy Al – 4.7% Mg – 0.32% Mn – 0.21% Sc – 0.09% Zr

Metal Science and Heat Treatment - The evolution of the structure and mechanical properties of sheets from alloy Al – 4.7% Mg – 0.32% Mn – 0.21% Sc – 0.09% Zr during warm...     

Effect of Modes of Spark Plasma Sintering on the Structure and Properties of Materials of the Ni – Cr – Si – B – C System

Metal Science and Heat Treatment - The influence of modes of spark plasma sintering (SPS) on the structure and properties of a self-fluxing powder material of the Ni – Cr – Si – B...     

Formation of Metastable Aluminides in Alloys of Al – Hf – Sc (Ti) Systems

Metal Science and Heat Treatment - The methods of optical and scanning electron microscopy and x-ray spectrum microanalysis are used to study and to compare the special features of formation of...     

Eutectic Morphology in Alloy Pb – 3.2% Cd – 0.08% Sr for Battery Grids

Metal Science and Heat Treatment - Ageing of supersaturated solid solution in Pb – 3.2% Cd – 0.08% Sr alloy is studied at 20 and 80°C by measuring hardness, and light and scanning...     

Friction welding – critical assessment of literature

Abstract

Friction welding is now well established as a means of joining many different types of materials, because it has proved itself to be a reliable and economical way of producing high quality welds. The present paper introduces different friction welding processes, their advantages and shortcomings. The history of friction welding and typical applications are also reviewed. In the context of friction welding, a number of subjects, such as frictional behaviour, joining mechanism, interface temperature and heat generation, still exist, where different concepts for explanation of the physical mechanisms have been proposed by different investigators. To clarify some inconsistencies in the interpretation of the friction welding process, a thorough review and critical assessment of the literature associated with this process is attempted.     

Modelling of electromagnetic processes in system 'welding arc – evaporating anode' Part 1 – Model of anode region

Abstract

A mathmatical model of electromagnetic processes occurring in the 'arc column – anode region – evaporating anode' system is presented. The anode region of electric arc with an evaporating metallic anode is described by a model, under which the non-equilibrium near anode plasma containing atoms and ions of the evaporated metal, along with atoms and ions of the ambient (inert) gas, is subdivided into a space charge layer immediately adjoining the anode surface and ionisation region adjacent to the arc column. This model allows determining the potential drop between welding arc column plasma and anode surface depending on the current density and plasma temperature near the anode, as well as upon the temperature of its surface.     

Friction stir welding – FSW applied to tailored blanks

The purpose of this study is joining main and branch gas pipes by friction welding without digging a paved road. By this development, only making a hole at the vertical side of the paved road, the branch pipe can be connected to the main pipe. In this study, an end face of branch pipe was welded to a side of the main pipe. Furthermore, considering that the gas main pipe is laid in the ground, the influence of mud on the joining state is examined. The experimental results are as follows.

• Branch pipe welding without digging a paved road was enabled by the friction welding method.

• The developed method does not require digging and repairing the paved road. Therefore, construction cost can be reduced, and traffic is not obstructed.

• Tensile strength and elongation of branch pipe friction welded joint were 17.7–17.8 MPa and 520–525%, respectively. These were nearly equal to those of base polyethylene.

• A large amount of mud was eliminated from the faying surface by friction. Therefore, the influence of mud on tensile strength and elongation was not recognized.

     

Zinc whisker growth from electroplated finishes – a review

Abstract

Electroplated zinc finishes have been associated with the electronics industry for many years as a result of their excellent corrosion resistance and relatively low cost. They are normally applied onto ferrous products to provide corrosion protection in a range of different environments. However, the formation of spontaneously grown whiskers on zinc-electroplated components, which are capable of resulting in electrical shorting or other damaging effects, can be highly problematic for the reliability of long life electrical and electronic equipment. The growth of zinc whiskers has been identified as the cause of some electrical and electronic failures in telecommunications and aerospace-based applications, with consequences ranging from mild inconvenience to complete system failures. Investigators have been striving to address the problems induced by whisker growth since 1940s. However, most research effort has been focused on tin whiskers, especially following European Union environmental legislation that restricted the use of lead (Pb), which when alloyed with tin (3–10% by weight) provided effective tin whisker mitigation. Compared with tin whisker research, much less attention has been paid to zinc whiskers. A number of mechanisms to explain zinc whisker growth have been proposed, but none of them are widely accepted and some are in conflict with each other. The aim of this paper is to review the available literature in regard to zinc whiskers, to discuss the reported growth mechanisms, to evaluate the effect of deposition parameters and to explore potential mitigation methods. This paper presents a chronologically ordered review of zinc whisker-related studies from 1946 to 2013. Some important early research, which investigated whisker growth in tin and cadmium, as well as zinc, has also been included.     

Elektrochemische Rauschmessungen – Innovation in der Korrosionsprüfung

Electrochemical noise measurements – Innovation in corrosion testing There are a lot of approved and standardized methods available for corrosion testing which have found wide application. Salt-spray testing, electrochemical polarization techniques and exposure tests in specific test media belong to these. Nevertheless, some questions remain unanswered and requirements unsatisfied. In particular, both the start of corrosion and the way it proceeds with time can often be examined only to an insufficient extent. Furthermore, the requirements of practical test conditions, acceptable effort and expenditure and shorter test durations lead to continuous development of these test methods. Within corrosion research, the analysis of electrochemical noise offers a simple, sensitive and virtually non-destructive measuring technique for assessment of the corrosion susceptibility of metallic materials and for the investigation of corrosion processes. The present status of knowledge concerning noise diagnostics in corrosion processes permits the application of this method not only to experimental tasks in the laboratory, but also to special problems in the context of practical corrosion monitoring. Furthermore, specific advantages of the technique enable its use to an increasing extent in supporting or improving conventional corrosion testing. The advantages here include obtaining additional information and shortening testing times (together with associated savings in resources such as manpower, energy, chemical reagents, etc.), thus resulting in state-of-the art corrosion testing.