Producing Ultrafine Grain Structure in AZ91 Magnesium Alloy Cast by Rapid Solidification

2014 ◽  
Vol 59 (1) ◽  
pp. 317-321 ◽  
Author(s):  
M. Szymanek ◽  
B. Augustyn ◽  
D. Kapinos ◽  
S. Boczkal ◽  
J. Nowak
Keyword(s):  
Magnesium Alloy ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Hot Extrusion ◽  
Solidification Process ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium ◽  
Ultrafine Grain Structure

Abstract The paper presents the technological aspect of the process of casting, crushing and plastic consolidation of semi-finished products from magnesium alloy. The aim of this study was to produce by the rapid solidification process a magnesium alloy from the MgAl9Zn1 family in the form of ribbons with ultrafine grain structure. The material cast in the melt spinning device was next crushed and subjected to the operation of cold consolidation and hot extrusion. The paper presents different stages of the process, including initial characterisation of the obtained material.

scholarly journals The Production of Material with Ultrafine Grain Structure in Al-Zn Alloy in the Process of Rapid Solidification

2014 ◽  
Vol 14 (2) ◽  
pp. 57-62
Author(s):  
M. Szymaneka ◽  
B. Augustyn ◽  
D. Kapinos ◽  
S. Boczkal ◽  
J. Nowak
Keyword(s):  
Rapid Solidification ◽  
Melt Spinning ◽  
Hot Extrusion ◽  
High Strength ◽  
Strength Properties ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Plastic Working ◽  
Metal Treatment ◽  
Ultrafine Grain Structure

Abstract In the aluminium alloy family, Al-Zn materials with non-standard chemical composition containing Mg and Cu are a new group of alloys, mainly owing to their high strength properties. Proper choice of alloying elements, and of the method of molten metal treatment and casting enable further shaping of the properties. One of the modern methods to produce materials with submicron structure is a method of Rapid Solidification. The ribbon cast in a melt spinning device is an intermediate product for further plastic working. Using the technique of Rapid Solidification it is not possible to directly produce a solid structural material of the required shape and length. Therefore, the ribbon of an ultrafine grain or nanometric structure must be subjected to the operations of fragmentation, compaction, consolidation and hot extrusion. In this article the authors focussed their attention on the technological aspect of the above mentioned process and described successive stages of the fabrication of an AlZn9Mg2.5Cu1.8 alloy of ultrafine grain structure designated for further plastic working, which enables making extruded rods or elements shaped by the die forging technology. Studies described in the article were performed under variable parameters determined experimentally in the course of the alloy manufacturing process, including casting by RS and subsequent fragmentation.

Effect of Rapid Solidification on the Structure and Mechanical Properties of AZ91 Magnesium Alloy

2012 ◽  
Vol 186 ◽  
pp. 120-123 ◽  
Author(s):  
Tomasz Tokarski
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Hot Extrusion ◽  
Protective Atmosphere ◽  
Material Structure ◽  
Dispersion Strengthening ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

The present paper reports an experimental investigation of rapid solidification (RS) influence on the structure and mechanical properties of commercial AZ91 magnesium alloy. In order to obtain RS material melt spinning process was applied in protective atmosphere, resulting in formation of 50 to 100 μm thickness RS ribbons. Application of plastic consolidation (PC) by hot extrusion to the highly fragmented magnesium strips allowed to obtain high bulk strength material. It was found that yield strength (YS) and ultimate tensile strength (UTS) of RS+PC material with comparison to the cast and extruded samples were increased from 220 MPa to 303 MPa and from 287 MPa to 385 MPa, respectively, while plasticity of the RS material was slightly decreased. It was noticed that the grain size of both materials was at the same level of 2 μm, thus higher mechanical properties of RS material was ascribed to dispersion strengthening caused by the high amount of fine (below 50 nm in diameter) Mg17Al12phases evenly distributed in the material structure.

Characterization of AM60 Magnesium Alloy Prepared by Rapid Solidification and Plastic Consolidation Technique

2010 ◽  
Vol 667-669 ◽  
pp. 997-1002
Author(s):  
Tomasz Tokarski
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Bulk Material ◽  
Structure Refinement ◽  
Hot Extrusion ◽  
Solidification Process ◽  
Protective Atmosphere ◽  
Material Structure

Magnesium and its alloys are attractive candidates for automotive and aerospace applications due to their relatively high strength and low density. However, their low ductility determined by hcp structure of material results in limitation of plastic deformation processing. In order to improve ductility as well as mechanical properties, structure refinement processes can be used. It is well known that effective refining of the material structure can be achieved by increasing the cooling rate during casting procedures, hence rapid solidification process (RSP) has been experimented for the fabrication of magnesium alloys. The present paper reports an experimental investigation on the influence of rapid solidification on the mechanical properties of AM60 magnesium alloy. In order to obtain RS material melt spinning process was applied in protective atmosphere, resulting in formation of RS ribbons. Following consolidation of the RS material is necessary to obtain bulk material with high mechanical properties, as so hot extrusion process was applied. It was noticed that application of plastic consolidation by hot extrusion is the most effective process to achieve full densification of material. For comparison purposes, the conventionally cast and hot extruded AM60 alloy was studied as well. The purpose of the present study was to investigate in detail the effect of rapid solidification and extrusion temperature on the structure and mechanical properties of the materials.

Corrosion of hot extrusion AZ91 magnesium alloy: I-relation between the microstructure and corrosion behavior

2011 ◽  
Vol 53 (5) ◽  
pp. 1960-1968 ◽  
Author(s):  
Tao Zhang ◽  
Yawei Shao ◽  
Guozhe Meng ◽  
Zhongyu Cui ◽  
Fuhui Wang
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Hot Extrusion ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

Effect of Heat Treatment on the Mechanical Properties of Wrought Al-Zn-Mg-Cu Alloy Cast by Rapid Solidification

2013 ◽  
Vol 765 ◽  
pp. 496-500 ◽  
Author(s):  
Dawid Kapinos ◽  
Marcin Szymanek ◽  
Bogusław Augustyn ◽  
Maciej Gawlik
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rapid Solidification ◽  
Solution Heat Treatment ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Cu Alloy ◽  
Optimum Heat ◽  
Ultrafine Grain Structure ◽  
Alloy Cast

The article presents the change in mechanical properties of AlZn9Mg2.5Cu1.8 alloy resulting from the process of solution heat treatment and aging. The heat treatment was performed on a unique UMSA (Universal Metallurgical Simulator and Analyzer) device. The aim of the study was to determine optimum heat treatment parameters for the tested alloy of ultrafine grain structure obtained by Rapid Solidification (RS). To achieve this purpose, heat treatment to the T4 and T6 condition was carried out. The solution heat treatment was carried out at a constant temperature of 460 °C for 2 hours, while the time - temperature parameters of the aging process varied. The treatment undertaken resulted in improved mechanical properties.

Superplasticity of an AZ91 Magnesium Alloy

2007 ◽  
Vol 567-568 ◽  
pp. 365-368 ◽  
Author(s):  
Zoltán Száraz ◽  
Zuzanka Trojanová ◽  
Talant Ryspaev ◽  
Volker Wesling
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Hot Extrusion ◽  
Az91 Magnesium Alloy ◽  
Physical Mechanisms ◽  
Heat Treated ◽  
Elongation To Failure ◽  
Az91 Magnesium ◽  
Two Stages

The superplastic deformation characteristics of the AZ91, the mostly used magnesium alloy, were investigated at various strain rates in the interval from 3x10-5 to 1x10-2 s-1 and temperature of 420 °C. To prepare superplastic alloys thermo-mechanical treatment was used. Cast materials were heat-treated in two stages, after homogenization at 415 °C for 10 h were submitted to the precipitation annealing at temperature in the range of 200-380 °C for 10 h, and deformed by hot extrusion. Microstructure of samples was observed by the light microscope Olympus. Strain rate sensitivity parameter m has been estimated by the abrupt strain rate changes method. The strong strain rate dependence of the m-parameter was found. The highest elongation to failure, 584%, was found for the samples aged at 380 °C. Possible physical mechanisms of the superplastic flow are discussed.

Influence of Hot Extrusion on Microstructure and Mechanical Properties of As-Cast AZ91 Magnesium Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 892-896
Author(s):  
Bao Hong Zhang ◽  
Zhi Min Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Yield Strength ◽  
Hot Extrusion ◽  
Extrusion Ratio ◽  
Extrusion Temperature ◽  
Az91 Magnesium Alloy ◽  
Microstructure And Mechanical Properties ◽  
Az91 Magnesium

In order to study the effect of plastic deformation on microstructure and mechanical properties of as-cast AZ91 magnesium alloy, experiments of hot direct extrusion were performed at different extrusion temperatures and different extrusion ratios. The microstructure and mechanical properties of extruded billets and extrudate were measured. Experimental results show that the grain size of as-cast AZ91 magnesium alloy can be dramatically refined by extrusion. Hot extrusion can obviously improve the mechanical properties of as-cast AZ91 magnesium Alloy, comparing with the pre-extruded billet, the tensile strength, yield strength and elongation of extrudate can be improved by at least 69%, 117% and 150% respectively. As the extrusion temperature increases, the tensile strength and yield strength of extrudate will increase. As the extrusion ratio increases, the tensile strength and yield strength of extrudate will increase at first and then fall. At the time of extrusion temperature of 420°C and extrusion ratio of 45, the highest tensile strength of 381Mpa and yield strength of 303MPa can be achieved for the extrudate.

scholarly journals Using High-Pressure Torsion to Achieve Superplasticity in an AZ91 Magnesium Alloy

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 681 ◽  
Author(s):  
Roberto B. Figueiredo ◽  
Terence G. Langdon
Keyword(s):  
High Pressure ◽  
Magnesium Alloy ◽  
Grain Boundary ◽  
High Pressure Torsion ◽  
Grain Boundary Sliding ◽  
Grain Structure ◽  
Strain Rates ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium ◽  
Boundary Sliding

An AZ91 magnesium alloy (Mg-9%, Al-1% Zn) was processed by high-pressure torsion (HPT) after solution-heat treatment. Tensile tests were carried out at 423, 523, and 623 K in the strain rate range of 10−5−10−1 s−1 to evaluate the occurrence of superplasticity. Results showed that HPT processing refined the grain structure in the alloy, and grain sizes smaller than 10 µm were retained up to 623 K. Superplastic elongations were observed at low strain rates at 423 K and at all strain rates at 523 K. An examination of the experiment data showed good agreement with the theoretical prediction for grain-boundary sliding, the rate-controlling mechanism for superplasticity. Elongations in the range of 300–400% were observed at 623 K, attributed to a combination of grain-boundary-sliding and dislocation-climb mechanisms.

Enhanced mechanical properties of as-cast AZ91 magnesium alloy by combined RE-Sr addition and hot extrusion

2020 ◽  
Vol 792 ◽  
pp. 139817 ◽  
Author(s):  
Aria Afsharnaderi ◽  
Mehrab Lotfpour ◽  
Hamed Mirzadeh ◽  
Massoud Emamy ◽  
Mehdi Malekan
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Hot Extrusion ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium
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