Search Results for magnesium

This article examines the composition and properties of magnesium and its alloys. It discusses alloy and temper designations, applications and product forms, and commercial alloy systems, and explains how alloying elements affect physical and mechanical properties, processing characteristics, and corrosion behaviors.

Magnesium occupies the highest anodic position on the galvanic series and can be subject to severe corrosion. The corrosion problem is due to the impurity elements iron, nickel, and copper. However, the use of higher-purity magnesium alloys has led to corrosion resistance approaching that of some of the competing aluminum casting alloys. This chapter begins with a general overview of magnesium metallurgy and alloy designations and moves on to discuss in detail the nominal compositions, mechanical properties, heat treatment, fabrication, and corrosion protection of magnesium casting alloys and wrought magnesium alloys. It also discusses the nominal compositions, properties, and applications of commercially pure zinc, zinc casting alloys, and wrought zinc alloys.

Magnesium, by volume, is two-thirds the weight of aluminum and one-quarter the weight of steel. It also has good damping capacity, giving it an edge over other metals in high-vibration environments. This chapter discusses the basic metallurgy, alloy designations, compositions, and mechanical properties of cast and wrought magnesium alloys. It also describes the processes used to produce magnesium parts, the causes and effects of corrosion, and the use of protective coatings and treatments.

This chapter discusses the effects of metallurgical factors on the corrosion resistance of magnesium alloys. The factors are chemical composition, heat treating, grain size, and cold-work effects. The chapter describes the causes of corrosion failures in magnesium alloys, namely heavy-metal contamination, blast residues, flux inclusions, and galvanic attack.

This chapter describes the effect of temperature and strain rate on the mechanical properties and forming characteristics of aluminum and magnesium sheet materials. It discusses the key differences between isothermal and nonisothermal warm forming processes, the factors that affect heat transfer, die heating techniques, and press systems. It also discusses the effect of forming temperature, punch velocity, blank size, and other parameters on deep drawing processes, making use of both experimental and simulated data.

Stress-corrosion cracking (SCC) in magnesium alloys was first reported in the 1930s and, within ten years, became the focus of intense study. This chapter provides a summary of all known work published since then on the nature of SCC in magnesium alloys and how it is related to composition, microstructure, and heat treatment. It describes the types of environments where magnesium alloys are most susceptible to SCC and the effect of contributing factors such as temperature, strain rate, and applied and residual stresses. The chapter also discusses crack morphology and what it reveals, provides information on proposed cracking mechanisms, and presents a practical approach for preventing SCC.