Metal Science and Heat Treatment

Botvina, L.

doi: 10.1007/BF01395221pmid: N/A

Recently in many areas of science we have seen increasing interest in critical phenomena, phase transitions, and the common characteristics of various processes. However, common characteristics have not been determined connecting processes of deformation, fracture, and crystallization. Obviously, the common nature of these processes, as for many other natural phenomena, should be sought on the basis of the thermodynamics of irreversible processes. Such an approach probably will allow us to connect phenomena occurring in solid, liquid, and gaseous media. This paper is devoted to analysis of the common characteristics of fracture and crystallization processes. We consider the characteristic features of the generation and accumulation of defects, and also nucleation of crystals of new phase. Both processes (fracture and crystallization) are analyzed from the standpoint of phase transition theory.

Shinyaev, A.

doi: 10.1007/BF01395222pmid: N/A

In the development of high-temperature alloys the use of refractory metals with a high melting point — Ta and W — for alloying is becoming conventional. These metals, and also the alloys based on them, may come into contact with metals and alloys whose melting points are much lower (for example, in composite-type materials). Upon heating there develop in the areas of contact of the metals differing in their melting point the processes of mutual diffusion, knowledge of which makes it possible to determine the chemical composition of the transition zone and the thermal stability of the composite material. Since production of the refractory metals involves great difficulties, intermediate products are prepared from them by the powder metallurgy method. The powder materials contain more defects, particularly pores, in comparison with the cast materials, which must be considered in studying the diffusion. In the present article we examine on the basis of experimental data and thermodynamic analysis the characteristics of the kinetics of the process of mutual diffusion of vanadium and the refractory metals in cast and powder variants at various temperatures.

Antsiferov, V.; Khramtsov, V.

doi: 10.1007/BF01395223pmid: N/A

The ranges of application of traditional technologies of powder metallurgy, which include holding under a pressure of (5–7)·102 N/mm2, are limited by the necessity of using expensive press equipment and attachments. This paper investigates the structure and properties of heat-treated die steels produced by a new method of molding — from stabilized suspensions of metallic powders. Optimal suspension compositions and sintering conditions are proposed.

Bezbakh, V.; Garasim, Y.; Yakushechkin, E.

doi: 10.1007/BF01395224pmid: N/A

A promising method for improving the strength properties of low-carbon steels is quenching from the intercritical temperature range. This process is quite simply carried out in metallurgical production on the rolling mill stream, as well as in a heat treating shop using separate heating. In this article the specifics of quenching from the intercritical temperature range with the use of electrical heating are considered.

Krasnikova, S.

doi: 10.1007/BF01395225pmid: N/A

The article investigates the effect of the parameters of heat treatment on the grain structure of maraging steels. A regime of heat treatment is suggested that ensures sufficiently high impact toughness of these steels.

Skotnikova, M.; Belov, Y.; Sokiryanskii, L.; Tsvetkova, G.; Sidorova, V.

doi: 10.1007/BF01395226pmid: N/A

Wear-resistant hard-alloy coatings (facings) of high-carbon iron-based alloys, with a composition close to that of tool steels, are used to increase the abrasive-wear resistance of working friction surfaces of products. Our aim here is to study the mechanical properties of the deposited metal after different technological conditions of coating deposition.

Zinkovich, P.; Rudoi, A.; Yakovenko, P.

doi: 10.1007/BF01395227pmid: N/A

Chromium and chromium-base alloys are promising materials for a number of areas of technology as the result of their unique properties. However, their increased brittleness at temperatures below 0.3 Tmelt (∼ 630°C) and, consequently, their low impact strength at room temperature retard their use and make it necessary to conduct investigations for the purpose of determining the conditions of use of these rnaterials. This article presents the results of impact tests of chromium and its alloys at temperatures up to 1100°C. Special attention was devoted to the test method for the purpose of obtaining reliable results.

Rabinovich, M.; Markuskev, M.

doi: 10.1007/BF01395228pmid: N/A

Crack resistance is an important characteristic of the structural strength of materials. The reliability criteria for articles depend upon it, i.e., ‘safe damage’ and ‘safe life.’ The first criterion is governed by the capacity of a material to provide article operation in the presence of cracks, and the second is governed by the time to generation of the first crack. Thus in order to evaluate crack resistance it is necessary to determine material resistance to crack generation and development. In this work resistance to crack generation and development is evaluated for wrought medium-strength aluminum alloys AMg6, AK4-1, and high-strength alloy V96ts which has a matrix (pseudo-single-phase) structure.

Popov, N.; Mart'yanov, V.; Ponomarev, V.

doi: 10.1007/BF01395229pmid: N/A

The literature gives little information on the effects of strain rate on the mechanical properties of alloys. The cracking resistance criterion Kλ has been determined for low-strength aluminum alloy AMts on small specimens, together with a series of standard and nonstandard strength, strain, and energy characteristics for plastic-strain rates of 10−3–103 sec−1. A dynamically loaded structure such as the central tube in a spiral explosive magnetic generator should be made of AMts alloy in the heat-treated state.