scholarly journals The microstructure and creep properties of as-cast Mg-Sn-Si-(Al) magnesium alloys

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Tomasz Rzychoń
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Ambient Temperature ◽  
Tensile Properties ◽  
Magnesium Alloys ◽  
Creep Resistance ◽  
Solution Treatment ◽  
Tensile Tests ◽  
Creep Tests ◽  
Creep Properties

Abstract Magnesium alloys containing rare earth metals exhibit good creep resistance up to 300 °C and good tensile properties at ambient temperature. The high cost of rare earth has led to studies regarding the creep resistance of Mg alloys with cheap alloying elements (Sn, Ca, Si) that could be substituted for Mg-RE alloys. In this paper, the influence of Si and Al on microstructure and mechanical properties of Mg-7Sn alloy was investigated using optical (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), tensile tests and creep tests at 200–250 °C. Microstructure of as-cast alloys consists of α-Mg matrix and intermetallic compounds at the interdendritic regions. Heat treatment consisting of solid solution treatment and ageing increases the tensile properties at ambient temperature due to the precipitation of the fine Mg2Sn phase. The creep resistance of aged Mg-7Sn alloy is poor. The addition of Si and Al to Mg-7Sn alloy has resulted in improving the creep resistance due to the refinement of Mg2Sn phase and the appearance of Mg2Si phase at the grain boundaries. The Mg-7Sn-1Si alloy exhibits better creep resistance at 200 °C than Mg-7Sn-5Si and Mg-7Sn-5Si-2Al alloys. The Mg-7Sn alloys with 5% Si have better creep properties at 250 °C in comparison to Mg-7Sn-1Si alloy.

Microstructure and Creep Properties of Selected Gravity Casting Magnesium Alloys

2016 ◽  
Vol 682 ◽  
pp. 372-379
Author(s):  
Tomasz Rzychoń
Keyword(s):  
Magnesium Alloys ◽  
Creep Resistance ◽  
Low Cost ◽  
Xrd Analysis ◽  
Phase Identification ◽  
Creep Tests ◽  
Gravity Casting ◽  
Creep Properties ◽  
Transmission Electron ◽  
Primary Crystals

In this paper microstructure and creep properties of Mg-Al-Ca-Sr, Mg-Zn-RE-Zr and Mg-Sn-Si gravity casting magnesium alloys are presented. The microstructure was characterized using light microscopy, scanning and transmission electron microscopy. Phase identification was made by SAED and XRD analysis. Creep tests were carried out in the temperature range from 180°C to 200°C at applied stress of 60 MPa. Microstructure of Mg-Al-Ca-Sr alloys composed of α-Mg grains and C36, C15 and C14 intermetallic compounds in the interdendritic regions. In case of Mg-Zn-RE-Zr alloys the dominant intermetallic compound is (Mg,Zn)12RE phase also located in the interdendritic regions. Microstructure of Mg-Sn-Si alloys after T6 heat treatment consists of plate-like precipitates of Mg2Sn phase, primary crystals of Mg2Si phase and globular Mg2Si phase. Among the alloys in this study, the low-cost Mg-5Al-3Ca-0.7Sr alloy has the best creep resistance. The other alloys, excluding the Mg-5Si-7Sn alloy, are characterized by a poorer creep resistance in compared to Mg-5Al-3Ca-0.7Sr alloy, however their creep resistance is better if compared to typical Mg-Al alloys. Creep resistance of Mg-5Si-7Sn alloy is very low.

Microstructure and Creep Resistance of Mg-Al-Ca-Sr Alloys

2014 ◽  
Vol 59 (1) ◽  
pp. 329-334 ◽  
Author(s):  
T. Rzychoń ◽  
B. Adamczyk-Cieślak
Keyword(s):  
Electron Microscopy ◽  
Creep Resistance ◽  
Volume Fraction ◽  
Intermetallic Phases ◽  
Phase Identification ◽  
Quantitative Metallography ◽  
Creep Tests ◽  
Creep Properties ◽  
Transmission Electron ◽  
Ebsd Technique

Abstract Microstructure and creep properties of cast Mg-Al-Ca-Sr alloys have been investigated. The microstructure was characterized using light microscopy, scanning and transmission electron microscopy. Phase identification was made by EBSD technique and by SAED analysis. The measurement of volume fraction of intermetallic phases was performed using quantitative metallography. Creep tests were performed at 180°C and at applied stress between 45 and 90 MPa. Microstructure of tested alloys composed of α-Mg grains and intermetallic compounds in the interdendritic regions. It was found that the addition of calcium and strontium improves creep resistance at 180°C.

The Influence of Tin on the Microstructure and Creep Properties of Mg-5Al-3Ca-0.7Sr-0.2Mn Magnesium Alloy

2012 ◽  
Vol 191 ◽  
pp. 151-158 ◽  
Author(s):  
Tomasz Rzychoń ◽  
Bartosz Chmiela
Keyword(s):  
Tensile Strength ◽  
Magnesium Alloy ◽  
Ambient Temperature ◽  
Magnesium Alloys ◽  
Creep Resistance ◽  
Creep Properties ◽  
Cast Condition

The paper presents results of microstructural investigations and creep properties of Mg-5Al-3Ca-0.7Sr-0.2Mn (ACJM53) and Mg-5Al-3Ca-0.8Sn-0.7Sr-0.2Mn (ACTJM531) magnesium alloys in as cast condition. The microstructure of the ACJM53 consists of α-Mg, (Mg,Al)2Ca - C36, Al3Mg13(Sr,Ca), Al2Ca - C15 and AlxMny. Additionally, the CaMgSn phase is observed in the ACTJM531 magnesium alloy. The addition of 0.8 wt% tin reduces the tensile strength at ambient temperature and creep resistance at 180°C.

Creep Properties and Interfacial Microstructure of SiC Whisker Reinforced Si3N4

1989 ◽  
Vol 170 ◽  
Author(s):  
Håkan A. Swan ◽  
Colette O'meara
Keyword(s):  
High Temperature ◽  
Creep Resistance ◽  
Interfacial Microstructure ◽  
Deformation Mechanisms ◽  
Amorphous Films ◽  
Creep Tests ◽  
Creep Properties ◽  
High Temperature Exposure ◽  
Temperature Exposure

AbstractPreliminary creep tests were performed on SiC whisker reinforced and matrix Si3N4 material fabricated by the NPS technique. The material was extensively crystallised in the as received material, leaving only thin amorphous films surrounding the grains. No improvement in the creep resistance could be detected for the whisker reinforced material. The deformation mechanisms were found to be that of cavitation in the form of microcracks, predominantly at the whisker/matrix interfaces, and the formation of larger cracks. Extensive oxidation of the samples, as a result of high temperature exposure to air, was observed for the materials tested at 1375°C.

scholarly journals Influence of strain rate and heat treatments on tensile and creep properties of Zn-0.15Cu-0.07Ti alloys

DYNA ◽  
2016 ◽  
Vol 83 (195) ◽  
pp. 77-83 ◽  
Author(s):  
María José Quintana Hernández ◽  
José Ovidio García ◽  
Roberto González Ojeda ◽  
José Ignacio Verdeja
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Strain Rates ◽  
Creep Tests ◽  
Design Problems ◽  
Creep Properties ◽  
Heat Treated ◽  
Zn Alloys

The use of Cu and Ti in Zn alloys improves mechanical properties as solid solution and dispersoid particles (grain refiners) may harden the material and reduce creep deformation. This is one of the main design problems for parts made with Zn alloys, even at room temperature. In this work the mechanical behavior of a Zn-Cu-Ti low alloy is presented using tensile tests at different strain rates, as well as creep tests at different loads to obtain the value of the strain rate coefficient m in samples parallel and perpendicular to the rolling direction of the Zn strip. The microstructure of the alloy in its raw state, as well as heat treated at 250°C, is also analyzed, as the banded structure produced by rolling influences the strengthening mechanisms that can be achieved through the treatment parameters.

Microstructure and Creep Properties of AJ62 and AE44 Die-Casting Magnesium Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1546-1551 ◽  
Author(s):  
Andrzej Kiełbus ◽  
Tomasz Rzychoń
Keyword(s):  
Magnesium Alloys ◽  
Creep Resistance ◽  
Cell Structure ◽  
Creep Behaviour ◽  
Die Casting ◽  
Tensile Creep ◽  
Creep Properties ◽  
Die Cast ◽  
Subgrain Formation ◽  
Good Creep Resistance

Microstructure and tensile creep behaviour of the die-cast AE44 and AJ62 magnesium alloys has been studied at temperatures between 175°C and 200°C and at stresses in the range from 60 to 75 MPa. At the 175°C the AJ62 and AE44 alloys exhibit good creep resistance after 120h creep deformation. At 200°C the AE44 alloy shows still good creep resistance, whereas in the case of AJ62 alloy the rapid decreasing of creep resistance has been observed. TEM observations reveal dislocations cell structure in AE44 alloy after creep test. In AJ62 alloy subgrain formation and decreasing the dislocation density have been observed.

Microstructure and Creep Properties of Casting Mg-8Al-0.3Mn Alloy Containing Ca and Sr

2011 ◽  
Vol 189-193 ◽  
pp. 1386-1392
Author(s):  
Yan Lou ◽  
Luo Xing Li
Keyword(s):  
Grain Boundaries ◽  
Creep Resistance ◽  
Elevated Temperatures ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Creep Tests ◽  
Creep Properties ◽  
Calcium Addition ◽  
Order Of Magnitude ◽  
Cast Microstructure

Microstructures and creep properties of AM80 alloy with calcium and strontium additions have been investigated by using OM, X-ray diffraction, SEM and creep tests. The results indicate that the as-cast microstructure of the AM80 alloy consists of the α-Mg matrix, bones-shaped Mg17Al12 and lamellar second precipitation phase at grain boundaries. Calcium and strontium can refine the grain size and the secondary phases. Calcium addition results in the formation of a fishbone Al2Ca eutectic phase in AM80 alloy. With the increase of calcium, reticular Al2Ca phase distribute at the grain boundaries. The creep resistance of the AM80 alloy is significantly improved by a small amount of strontium and calcium addition due to the formation of a grain boundary network consisting of the high melting point Al2Ca phase. Microstructure observations performed on the sample after creep testing reveal that the phase is distorted during creep, reflecting its formation in the as-cast microstructure is unbeneficial to creep properties of the AM80 alloy. The creep resistance of the alloy at elevated temperatures was remarkably increased when calcium was added combined with strontium. The highest creep resistance was obtained from the alloy with xSr and y3Ca addition and its steady state creep rate reached as low as 3.941×10-8s-1, one order of magnitude lower than that of alloy AM80 without strontium and calcium additions.

Constitutive Equations for Tensile and Creep Behavior of a 9 Cr-1 MO Steel

1975 ◽  
Vol 97 (4) ◽  
pp. 258-263
Author(s):  
F. V. Ellis ◽  
J. E. Bynum ◽  
B. W. Roberts
Keyword(s):  
Constitutive Equation ◽  
Test Data ◽  
Constitutive Equations ◽  
Tensile Tests ◽  
Temperature Dependent ◽  
Creep Tests ◽  
Creep Properties ◽  
Hardening Mechanism ◽  
Strain Relationship ◽  
Analysis Computer

This paper describes an investigation of the tensile and creep properties of annealed 9 Cr-1 Mo steel. Tensile tests were conducted at temperatures from 70 to 1050 F while creep tests were conducted at 750, 850, 950, and 1050 F with stresses from 4 to 52 ksi. From the tensile test data, a constitutive equation was developed for the stress-plastic strain relationship. This equation was based on a two-stage hardening mechanism and combined power law and exponential functions. From the creep test data, isochronous stress-strain curves were constructed out to 104 hr. These curves were extrapolated to 105 hr and to lower stresses using a parametric analysis procedure. Additionally, a creep constitutive equation capable of describing the total creep curve, including the tertiary region, was developed. This equation, having three stress and temperature dependent parameters predicted creep curves which were in good agreement with the actual curves. Both the time-independent (tensile) and time-dependent (creep) constitutive equations are suitable for use in finite element stress analysis computer programs.

Influence of Solution Temperature on Compositions Segregation and Creep Behavior of a Single Crystal Nickel-Based Superalloy

2013 ◽  
Vol 747-748 ◽  
pp. 690-696 ◽  
Author(s):  
Su Gui Tian ◽  
Y.C. Xue ◽  
Z. Zeng
Keyword(s):  
Creep Resistance ◽  
Solution Treatment ◽  
Solution Temperature ◽  
Medium Temperature ◽  
Creep Properties ◽  
Nickel Based Superalloy ◽  
Microstructure Observation ◽  
Composition Segregation ◽  
Deformation Features ◽  
Different Temperatures

By means of solution treatment at various temperatures, creep properties measurement and microstructure observation, the effects of heat treatment on composition segregation and creep properties were investigated. Results show that the various segregation extents of the elements are displayed in the alloys solution treated at different temperatures, and the segregation extent of the elements is improved with the solution temperature elevated, which may obvious improve the creep resistance of the alloy. And no rafted structure of the γ phase is detected in the alloy during creep at medium temperature. The deformation features of the alloy during creep at medium temperature are that the slipping of dislocations is activated in the γ matrix channels, and dislocations shearing into the γ phase may be decomposed to form the configuration of partials + stacking faults, which may hinder the cross-slipping of the dislocations to improve the creep resistance of the alloy.

scholarly journals Microstructures and High Temperature Tensile Properties of As-Aged Mg-6Zn-1Mn-4Sn-(01, 0.5 and 1.0) Y Alloys

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Guangshan Hu ◽  
Meipeng Zhong ◽  
Changfa Guo
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Tensile Properties ◽  
Fracture Mechanism ◽  
Tensile Tests ◽  
Mixed Mode Fracture ◽  
Transgranular Fracture ◽  
Fracture Type ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

The microstructures and high-temperature tensile properties of as-aged Mg-6Zn-1Mn-4Sn-(0.1, 0.5 and 1.0) Y (wt.%, ZMT614-Y) alloys were investigated by optical microscopy (OM), X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-temperature tensile tests. The tensile temperatures were 150 °C, 200 °C, 250 °C and 300 °C, respectively. The results showed that the phase compositions of as-aged alloys were α-Mg, α-Mn, MgZn2, Mg2Sn, and MgSnY phases. The Mg2Sn and MgSnY high-temperature phases inhibited grain growth in the heat treatment and tensile processes. The as-aged ZMT614-0.5Y alloy has the best high-temperature mechanical properties, with yield strength (YS), ultimate tensile strength (UTS), and elongation values of 277 MPa, 305 MPa, and 16.7%, respectively, at 150 °C. As the tensile temperature increased to 300 °C, the YS and UTS decreased to 136 MPa and 150 MPa, and elongation increased to 25.5%. The fracture mechanism changed as the tensile temperatures ranged from 150 °C to 300 °C, from the transgranular fracture type at temperatures of 150 °C and 200 °C, to the transgranular and intergranular mixed-mode fracture type when tensile temperatures increased to 250 °C, to an intergranular fracture mechanism at 300 °C.

Sign in / Sign up

Export Citation Format

Share Document