Effects of Precipitates and Alloying Element on Microstructure and High Temperature Properties of Mg-Al Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 537-540 ◽  
Author(s):  
Yeon Jun Chung ◽  
Kwang Seon Shin
Keyword(s):  
High Temperature ◽  
Tensile Properties ◽  
Casting Machine ◽  
Tensile Tests ◽  
Al Alloys ◽  
Thermally Stable ◽  
Alloying Element ◽  
High Temperature Mechanical Properties ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

The effects of precipitates and alloying element on the high temperature tensile properties of Mg-Al alloys were investigated in this study. In order to modify the precipitation behavior and microstructure of Mg-Al alloys, Sr and/or Mm (Misch metal) were added to the Mg-9Al and AZ91 alloys. All test specimens used in this study were die-cast on a 320 ton cold chamber high-pressure die-casting machine and the microstructures of the specimens were examined by optical and scanning electron microscopy. Tensile tests were carried out at room temperature, 150oC and 200oC at a strain rate of 2×10-4/sec. The microstructure analyses revealed that thermally stable MgAlSr and AlMm compounds were precipitated in the Sr and/or Mm added alloys and these compounds suppressed the precipitation of the discontinuous Mg17Al12 phase at grain boundaries. The high temperature mechanical properties of the Mg-Al alloys were found to increase with the addition of Sr and/or Mm. It was concluded that the addition of Sr and/or Mm improved high temperature tensile properties of the Mg-Al alloys by the formation of thermally stable precipitates.

The Effect of Microalloying B on the High Temperature Mechanical Properties of Ti3Al

1988 ◽  
Vol 133 ◽  
Author(s):  
Joseph W. Newkirk ◽  
Gerald B. Feldewerth
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Tensile Properties ◽  
Grain Refinement ◽  
High Temperature Mechanical Properties ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

ABSTRACTThe effect of adding boron to Ti3Al on the microstructure and high temperature tensile properties has been studied. Boron caused a large grain refinement that dominated the tensile properties at all temperatures. Particles of Ti2B were found in all of the boron containing alloys. TiB was found only at concentrations of 0.1% B or more.

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.

Effects of Alloying Elements on Mechanical Properties of Mg-Al Alloys

2005 ◽  
Vol 488-489 ◽  
pp. 845-848 ◽  
Author(s):  
Yeon Jun Chung ◽  
Jung Lae Park ◽  
Nack J. Kim ◽  
Kwang Seon Shin
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Casting Machine ◽  
Al Alloys ◽  
Alloying Elements ◽  
Tensile Creep ◽  
Thermally Stable ◽  
Creep Tests ◽  
High Temperature Mechanical Properties

The effects of alloying elements on the microstructure and high temperature mechanical properties of Mg-Al alloys were investigated in this study. In order to improve the high temperature mechanical properties, Sr or Mm was added to the Mg-9Al alloy. The effect of Sn on the Mg-9Al alloy was also examined since Sn was expected to improve the high temperature mechanical properties by forming the thermally stable Mg2Sn phase. The specimens used in this study were produced on a 320 ton cold chamber high-pressure die casting machine. The microstructures of the specimens were examined by optical and scanning electron microscopy and tensile and creep tests were performed at elevated temperatures. Tensile tests were carried out at room temperature, 150oC and 200oC using an initial strain rate of 2×10-4/sec. In addition, tensile creep tests were conducted at the stress levels of 50 MPa and 70 MPa. From the microstructure analyses of the specimens after heat treatment at 400oC for 12 hours, it was found that most of the Mg17Al12 precipitate dissolved into the matrix, while the thermally stable phases continued to exist. The high temperature mechanical properties of the Mg-9Al alloys were found to improve significantly with the additions of Sr, Mm and Sn, due to the formation of the thermally stable precipitates.

scholarly journals Microstructure and High Temperature Tensile Properties of Mg–10Gd–5Y–0.5Zr Alloy after Thermo-Mechanical Processing

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 980 ◽  
Author(s):  
Guohua Wu ◽  
H. Jafari Nodooshan ◽  
Xiaoqin Zeng ◽  
Wencai Liu ◽  
Dejiang Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Tensile Properties ◽  
Test Temperature ◽  
Mechanical Processing ◽  
Twin Boundaries ◽  
High Temperature Mechanical Properties ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

The microstructure, high-temperature tensile properties and fracture behavior of the Mg-10Gd-5Y-0.5Zr alloy after thermo-mechanical processing (pre-tension between solution and aging treatment) were investigated. The pre-deformed alloy shows the accelerated aging kinetics compared to the un-deformed alloy. Microstructure of pre-deformed samples showed not only the homogeneous nucleation of the precipitate but also heterogeneous nucleation of precipitates on the dislocation and twin boundaries. Tensile results show that the pre-deformation enhanced the strength of the alloy, while it deteriorates the ductility of the alloy. The ultimate tensile strength (UTS) of the T6 treated un-deformed and pre-deformed alloy at room temperature are 331 MPa and 366 MPa, respectively. Tensile strength of the T6 treated alloy in both un-deformed and deformed conditions was enhanced by raising the test temperature and then reduced by further raising the test temperature. The higher strength of the pre-deformed alloy could be related to the higher density of the precipitates, which grow on the twin boundaries and can hinder the dislocation movement and strengthen the alloy. The results shows that thermo-mechanical processing can significantly improve the room- and high-temperature mechanical properties and enhance the formation of precipitates in Mg-10Gd-5Y-0.5Zr alloy, which can lead to wider application of the alloy in industries such as aerospace or powertrains that need better room- and high-temperature mechanical properties.

Improved High Temperature Tensile Properties of Ti-6Al-4V Alloy by Plasma Sprayed Coating

2008 ◽  
Vol 580-582 ◽  
pp. 547-550
Author(s):  
Cui Li ◽  
Wei Qi ◽  
Kutsuna Muneharu
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
Tensile Properties ◽  
Tensile Tests ◽  
Oxygen Penetration ◽  
Subsurface Zone ◽  
Coated Alloy ◽  
Sprayed Coating ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

A zircon coating was applied on the surface of Ti-6Al-4V alloy by plasma spray and its effect on the high temperature tensile properties of the alloy as well as the oxidation behavior of the alloy were studied. Tensile tests were conducted at 850°C with different strain rates of 10-4s-1,10-3s- 1, 10-2s-1 and 10-1s-1. The results show that the elongation of the coated specimens is higher than that of the uncoated ones, while the ultimate tensile strength of the alloy is not changed. An oxide film had formed on the surface of uncoated Ti-6Al-4V alloy, however no such oxide film was found on the coated alloy at the early of stage. The coating can prevent oxygen penetration into the substrate thus prevent embrittlement of the subsurface zone. The ductility could be improved by means of the zircon coating. The optical micrographs of the specimens show little change in microstructures of the coated and uncoated specimens. Zircon coating has no effect on the microstructure of the substrate alloy.

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