Die Forging of High-Strength Magnesium Alloys – the Structure and Mechanical Properties in Different Heat Treatment Conditions / Kucie Matrycowe Wysokowytrzymałych Stopów Mg – Struktura I Własciwosci Mechaniczne W Róznych Stanach Obróbki Cieplnej

2013 ◽  
Vol 58 (1) ◽  
pp. 127-132 ◽  
Author(s):  
B. Płonka ◽  
M. Lech-Grega ◽  
K. Remsak ◽  
P. Korczak ◽  
A. Kłyszewski

The object of this study was to develop parameter of the die forging process, such as feedstock temperature and to investigate her impact on the structure and mechanical properties of magnesium alloys in different heat treatment conditions. Tests were carried out on a 2,5MN maximum capacity vertical hydraulic press using forgings of sample (model) shapes. Then, based on the results obtained in previous work, research was carried out to develop for items forged from magnesium alloys the parameters of heat treatment to the T5 and T6 condition in the context of achieving possibly homogeneous and fine-grained structure and, consequently, high mechanical properties.

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647 ◽  
Author(s):  
Bingrong Zhang ◽  
Lingkun Zhang ◽  
Zhiming Wang ◽  
Anjiang Gao

In order to obtain high-strength and high-ductility Al–Si–Cu–Mg alloys, the present research is focused on optimizing the composition of soluble phases, the structure and morphology of insoluble phases, and artificial ageing processes. The results show that the best matches, 0.4 wt% Mg and 1.2 wt% Cu in the Al–9Si alloy, avoided the toxic effect of the blocky Al2Cu on the mechanical properties of the alloy. The addition of 0.6 wt% Zn modified the morphology of eutectic Si from coarse particles to fine fibrous particles and the texture of Fe-rich phases from acicular β-Fe to blocky π-Fe in the Al–9Si–1.2Cu–0.4Mg-based alloy. With the optimization of the heat treatment parameters, the spherical eutectic Si and the fully fused β-Fe dramatically improved the ultimate tensile strength and elongation to fracture. Compared with the Al–9Si–1.2Cu–0.4Mg-based alloy, the 0.6 wt% Zn modified alloy not only increased the ultimate tensile strength and elongation to fracture of peak ageing but also reduced the time of peak ageing. The following improved combination of higher tensile strength and higher elongation was achieved for 0.6 wt% Zn modified alloy by double-stage ageing: 100 °C × 3 h + 180 °C × 7 h, with mechanical properties of ultimate tensile strength (UTS) of ~371 MPa, yield strength (YS) of ~291 MPa, and elongation to fracture (E%) of ~5.6%.


2021 ◽  
Vol 410 ◽  
pp. 197-202
Author(s):  
Pavel P. Poleckov ◽  
Olga A. Nikitenko ◽  
Alla S. Kuznetsova

This study considers the influence of various heat treatment conditions on the change of steel microstructure parameters, mechanical properties and cold resistance at a temperature of-60 °C. The common behavior of these properties is considered depending on the heating temperature used for quenching and subsequent tempering. Based on the obtained results, heat treatment conditions are proposed that provide a combination of a guaranteed yield point σ0.2 ≥600 N/mm2 with a low-temperature impact toughness KCV-60 ≥50 J/cm2 and plasticity δ5 ≥17%. The obtained research results are intended for industrial use at the mill "5000" site of MMK PJSC.


2014 ◽  
Vol 941-944 ◽  
pp. 1761-1768
Author(s):  
Jun Lin ◽  
Feng Kang ◽  
Chuan Kai Hu ◽  
Qiang Chen ◽  
Zu De Zhao

Taking the geometric configuration of complex-shape forging into account, the isothermal split-die forging method, which is one multi-way die forging technology and can be operated on the general hydraulic press, is employed. The temperatures of billed and dies are 420°C and 380°C in the isothermal forging process. The coupled thermo-mechanical finite element method (FEM) is used to analyze the forging process. FEM calculation results show several folds had been formed in the final forging process due to unreasonable geometric configuration of preform. The folds mechanism is that direction of velocities become cross on the surface of billet, and the folds can be avoided if the direction would be kept convex. And then the preform is redesigned. A set of isothermal precision forming equipment is designed and manufactured. The experimental results verify the selected process and preform configuration. And all of the hardness, dimensional accuracy and surface quality of the forgings obtained by the equipments satisfy the requirements.


2021 ◽  
Vol 410 ◽  
pp. 221-226
Author(s):  
Mikhail V. Maisuradze ◽  
Maxim A. Ryzhkov ◽  
Dmitriy I. Lebedev

The features of microstructure and mechanical properties of the aerospace high strength steel were studied after the implementation of various heat treatment modes: conventional oil quenching and tempering, quenching-partitioning, austempering. The dependence of the mechanical properties on the tempering temperature was determined. The basic patterns of the formation of mechanical properties during the implementation of isothermal heat treatment were considered. The optimal heat treatment conditions for the studied steel were established.


2021 ◽  
Vol 904 ◽  
pp. 124-130
Author(s):  
Si Yang Xu ◽  
Ying Long Li ◽  
Mu Xin Zhang ◽  
Yi Fu Jiang ◽  
Hua Ding

Due to its high strength, excellent electrical conductivity and high resistance to stress corrosion, Cu-Ni-Sn alloy has been selected as a kind of advanced metal material which can be used as the manufacture of springs, connectors, bearings and so on. In addition, the addition of Nb can efficiently improve the comprehensive properties of the alloy. In the present work, the effect of heat treatment conditions on microstructure and mechanical properties were studied in a Cu-9Ni-6Sn-0.22Nb alloy by means of optical microscopy (OM), transmission electron microscopy (TEM), tensile test and microhardness tests. The results show that before ageing, a large number of fine γ precipitates with DO22 type structure are distributed on the matrix. With the prolongation of ageing time, the ultimate tensile strength (UTS), yield strength (YS) and Vickers hardness increased firstly, and then decline. The reason can be attributed to the occurrence of spinodal decomposition and the formation of discontinuous precipitation (DP). At first, spinodal decomposition induced the enhanced interaction between dislocations and internal stress field, resulting in an increase of mechanical properties. Then the increased DP at grain boundaries leads to the decline of strength in the material. Finally, the relationship between the microstructure and the electrical conductivity was also analyzed, and the results show that the electrical conductivity increased with ageing time/ageing temperature increasing for the present alloy. Through the analysis of Matthiessen’ s rule, the variation of electrical resistivity depends on precipitates, solute atoms, dislocations, vacancies and grain boundaries, and the precipitates play an important role among them. Besides, more precipitates improve electrical conductivity. Therefore, the increase of ageing time/ageing temperature induced the increase of DP, resulting in an increase of electrical conductivity.


2014 ◽  
Vol 59 (1) ◽  
pp. 371-375
Author(s):  
B. Płonka ◽  
P. Korczak ◽  
K. Remsak ◽  
M. Lech-Grega

Abstract The paper presents the results of the die forging tests of a modified EN AW-6101 alloy with the addition of Zr, using two types of the feedstock materials. The first feedstock materials were ingots cast in a vertical semi-continuous process, the second feedstock materials were extruded rods. The die forging process was carried with parameters enabling “on line” heat treatment (T5 temper). For comparison, forgings were also heat treated to the T6 temper and to thermo-mechanical treated to the T8 and T9 temper. Then forgings made from both feedstock materials were characterised in terms of structure, mechanical properties and electrical conductivity.


Author(s):  
E. F. Volkova ◽  
V. A. Duyunova ◽  
I. V. Mostyaev ◽  
M. V. Akinina

An approach to creating high-strength deformable magnesium alloys for developing a fine-grained structure and a favourable phase composition is considered. The possibility of a noticeable improvement in the characteristics of magnesium alloys by introducing REEs in certain ratios for the formation of long-period phases (LPSO phases) is considered. The regularities of formation and features of the influence of a fine structure on the properties of a new-generation magnesium alloy of the VMD16 brand are studied.


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