Interaction of Components in Glass-Forming Melts of Iron and Nickel with Titanium,Zirconium, and Hafnium II. Temperature–Concentration Dependence of Thermodynamic Mixing Functions of Liquid Alloys

Powder Metallurgy and Metal Ceramics - The thermodynamic properties of liquid alloys in glass-forming systems were described in the framework of the associated solution model (ASM) according to the...     

Using mineralogy to optimize gold recovery by direct cyanidation

The complete and accurate gold deportments of direct cyanide leach residues provide a clear picture of the occurrence of unrecovered gold and identify causes for poor extraction. Based on the independent measurement of each form and carrier of unleached gold, opportunities for recovery optimization can be assessed more accurately by providing meaningful targets and can help identify the means to achieve such targets. In ten of 14 leach plants surveyed, 23% of the unrecovered gold could be extracted without finer grinding. For more information, contact S. Chryssoulis, AMTEL, 205-100 Collip Circle, London, Ontario, Canada N6G 4X8; (519) 858-5037; fax (519) 858-5038; e-mail amtel@skynet.ca.     

Features of Implementing Thermomechanical Rolling in Various Types of Mills

Metallurgist - Features of thermo-mechanical rolling in various types of rolling mills are studied: plate mill (continuous, semicontinuous), Steckel mill, and a casting and rolling complex with a...     

Structure and Properties of an Ni3Al Intermetallic Compound Formed as a Result of Spark Plasma Sintering of the Powder Mixtures Prepared by Various Methods

Metallurgist - The paper described the structure and mechanical properties of nickel aluminide (Ni3Al) obtained by spark plasma sintering of the two compositions of nickel and aluminum powder...     

Defining Specifications for Custom Products: A Multi-Attribute Negotiation Approach

Defining product specifications so that customers' needs could be well matched with suppliers' capabilities is a very challenging task in custom product design. This research links technical requirements on product design with product management issues and formulates specification definition as multi-attribute negotiation. Specification negotiation is modeled as an iterative process of give and take in search of a mutually acceptable configuration. A negotiation support system is developed based on a product configuration system to identify among the multiple attributes what to give, what to take, and by how much so as to facilitate specification negotiation operationally.     

Characterization of ultrafine La x Sr1−x MnO3 powder prepared by spray pyrolysis

The characterization of La _x Sr_1−x MnO₃ powders produced by spray pyrolysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation, specific surface area (Brunauer-Emett-Teller), and particle size distribution measurements shows that the resultant large particles are loose agglomerates consisting of many small particles. However, the sintered tiny particles can form hard agglomerates, and the particle size increases remarkably. The structures of the powders before and after sintering were identified by x-ray diffraction (XRD). The study of the electrical property of the powder shows that the powder is a metallic conductor. In a reducing atmosphere, the powder can be decomposed. When the powder is cofired with yttria-stabilized zirconia 5% (YSZ) powder at 1200 °C for 5 h, no new phase is produced, and the powder remains a single provskite hexagonal-rhombohedral structure.     

Effect of the zone of plastic deformation of the fractal properties of a fracture surface

In order to determine the effect of the plastic zone on the fractal properties of a fracture surface, specimens of medium-carbon steels are studied after tough and brittle fracture. A fractal analysis is conducted for each specimen by the method of vertical sections. The sizes of the determining parameters of the fractures and plastic zones under the fracture surfaces are determined by measuring the Knoop microhardness. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 21–25, July, 1997.     

Calculated hardenability for improved consistency of properties in heat treatable engineering steels

Hardenability is one of the most important parameters controlling the heat treated properties of engineering steels. It affects the consistency of response for microstructure, hardness, strength, toughness, and dimensional change (distortion). This study illustrates that a major benefit of controlling hardenability is improving the consistency of dimensional distortion resulting from heat treatment. To facilitate the supply of steels to hardenability limits, especially restricted hardenability, a new technique was developed for the prediction of Jominy hardenability from chemical composition. The technique, termed the “Database Method,” uses measured Jominy hardenability and chemical composition data, contained in a database, to calculate the hardenability for a query composition. Using up to ten known steels, selected from the database with compositions closely matching that of the query steel, a small adjustment is made to the measured hardenability of each known steel allowing for the small difference in composition between the query and chosen steel. The final calculated result for the query steel is taken as the average of the various estimates. The basis of the Database Method is explained, and the advantages are illustrated for selecting engineering grades.