Thermal analysis and electron probe microanalysis of the AK6 aluminum alloy

Processes of melting the samples of industrial AK6 aluminum alloy in cast and homogenized states are studied using thermal analysis with the subsequent numerical differentiation with respect to time of heating curves in a temperature range from 300 to 670°C. The temperatures of nonequilibrium solidus, equilibrium solidus, and liquidus are evaluated. The microstructure of cast and homogenized alloy samples is studied and the local chemical composition of the aluminum host and phases is determined. © 2013 Allerton Press, Inc

Parametric synthesis of linear regulator in interval system with guaranteed root quality indices

Automatic control system containing proportional-plus-integral action regulator and control object which has interval specified parameters has been considered. Using robust expansion of root-locus method the technique of synthesis of proportional-plus-integral action regulator parameters guaranteeing minimal degree of stability and maximal degree of system oscillation was developed. The technique is based on vertex analysis of root quality indices applying the equation of Theodorchik-Evans. The numeric illustration is give

Arrangement of dominant poles localization areas of automatic control interval system in specified truncated sector

Characteristic polynomial of automatic control system has been considered. Its coefficients contain linearly entering interval parameters of control object and regulator adjustable parameters. The technique of determining regulator tunings supporting specified root quality indices of interval system was developed. The numerical illustration is give

СТРУКТУРА И МЕХАНИЧЕСКИЕ СВОЙСТВА СЛИТКОВ И ПРОФИЛЕЙ ИЗ АЛЮМИНИЕВОГО СПЛАВА НА ОСНОВЕ СИСТЕМЫ AL-MG-MN

Commercial ingots and hot-pressed rolled sections of Al-Mg-Mn alloy doped with zinc, scandium, zirconium, chromium, and vanadium have been studied using optical microscopy, thermal analysis, electron microscopy, and electron-probe microanalysis. The compositions of the phase constituents and aluminum matrix of the alloy are determined. The sensitivity of the alloy to the formation of complex intermetallic compounds during solidification is revealed. The mechanical properties of ingots and rolled sections are determined. © 2013 Pleiades Publishing, Ltd

Role of metallurgical factors in structure and property formation for thick plates of alloys of the Al-Cu-Mg-Mn system

The role of chemical composition is studied in thick plate structure and property formation for alloys of the Al-Cu-Mg-Mn system. It is shown that in order to correct the chemical composition of aluminum alloys it is necessary to consider the alloying element compatible solubility limit within an aluminum matrix at the heating temperature for hardening and the proportion of alloying elements participating in forming almost insoluble phases with impurity elements. An important role is also played by alloying elements formed with reaction of excess phases, although they are soluble but cannot be dissolved during heating for hardening due to saturation of α-solid solution with alloying elements. © 2013 Springer Science+Business Media New York

Phase formation during nonequilibrium crystallization of Al-Mg-Si system alloys

Nonequilibrium crystallization of alloys of the Al-Mg-Si system, and also their structure and phase composition in a cast condition are studied. Thermal analysis is used to establish phase transformation temperature ranges, occurring during nonequilibrium crystallization of industrial aluminum alloys AD31 and AD33. x-Ray microanalysis is used to determine metastable phase composition in the alloys in a cast condition. © 2013 Springer Science+Business Media New York

Parametric identification of the controlled object based on transfer characteristics

Classical identification techniques are shown; their strengths and shortcomings are analyzed. The correlations associating direct indexes of transfer characteristic quality of the controlled object and its pole-zero configuration are received. The identification technique of the linear dynamic object based on correlations is developed. The numerical model is given

A Single-Loop DC Motor Control System Design with a Desired Aperiodic Degree of Stability

The application of the original analytical approach for Pi-controller synthesis of a stable second-order plant is considered. This approach allows finding controller parameters without any intensive computing by using the direct expressions. The plant model is obtained on the basis of identification, which is based on the automated real-interpolation method. The results of natural experiments are given