scholarly journals The Influence of La and Ce on Microstructure and Mechanical Properties of an Al-Si-Cu-Mg-Fe Alloy at High Temperature

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 384
Author(s):  
Andong Du ◽  
Anders E. W. Jarfors ◽  
Jinchuan Zheng ◽  
Kaikun Wang ◽  
Gegang Yu

The effect of lanthanum (La)+cerium (Ce) addition on the high-temperature strength of an aluminum (Al)–silicon (Si)–copper (Cu)–magnesium (Mg)–iron (Fe)–manganese (Mn) alloy was investigated. A great number of plate-like intermetallics, Al11(Ce, La)3- and blocky α-Al15(Fe, Mn)3Si2-precipitates, were observed. The results showed that the high-temperature mechanical properties depended strongly on the amount and morphology of the intermetallic phases formed. The precipitated tiny Al11(Ce, La)3 and α-Al15(Fe, Mn)3Si2 both contributed to the high-temperature mechanical properties, especially at 300 °C and 400 °C. The formation of coarse plate-like Al11(Ce, La)3, at the highest (Ce-La) additions, reduced the mechanical properties at (≤300) ℃ and improved the properties at 400 ℃. Analysis of the strengthening mechanisms revealed that the load-bearing mechanism was the main contributing mechanism with no contribution from thermal-expansion mismatch effects. Strain hardening had a minor contribution to the tensile strength at high-temperature.

1986 ◽  
Vol 81 ◽  
Author(s):  
S. E. Hsu ◽  
N. N. Hsu ◽  
C. H. Tong ◽  
C. Y. Ma ◽  
S. Y. Lee

AbstractHigh temperature mechanical properties of various Zr and Cr strengthened single phase Ni3Al are investigated, with emphasis on the ability of each element to elevate Tp, the temperature corresponding to the peak yield strength. It is observed that Zr is a very effective strengthener, more so below Tp than above it, while a combination of Cr and Zr is capable of shifting Tp to a higher temperature. The combination results in an effective improvement of the rupture strength of Ni3Al. The strengthening mechanisms of each element will be discussed in this paper.


2014 ◽  
Vol 783-786 ◽  
pp. 580-583 ◽  
Author(s):  
Murugesan Jayaprakash ◽  
De Hai Ping ◽  
Y. Yamabe-Mitarai

Titanium (Ti) alloys are widely used in aerospace industries successfully up to 600°C. Increasing the operating temperature and performance of these alloys would be very useful for fuel economy. Numerous numbers of research works has been focused on the improvement of the high temperature performances of Ti alloys. It has been well known that Zirconium (Zr) is one of the important solid-solution strengthener in Ti-alloys. In the present study, the effect of Zr addition on the microstructure and mechanical properties of the near–α Ti-Al-Zr-Sn based alloys has been investigated.The compression test results showed that Zr addition significantly improves both room temperature and high temperature strength. The results obtained were explained based on the microstructural observation, room temperature and high temperature compressive tests.


2010 ◽  
Vol 163-167 ◽  
pp. 2949-2952
Author(s):  
Jian Qing Qian ◽  
Ji Ping Chen ◽  
Bao Qiao Wu ◽  
Jie Ca Wu

The fire-resistant hot-rolled H-beam steel is the newly developed structure material. The development situation of the fire-resistant H-beam steel is briefly introduced. The chemical composition, microstructure, room temperature and high temperature mechanical properties and weldability of several batches of the developed domestic fire-resistant hot-rolled H-beam steels are comprehensively analyzed. The results show that the newly developed hot-rolled fire-resistant H-beam steel has very high room temperature strength, certain high temperature strength, good welding performance, but the toughness needs to be further improved. The performance of web and flange of H-beam steel has large gap.


Author(s):  
J. Liu ◽  
J. X. Dong ◽  
M. Z. Chen ◽  
X. S. Xie

The nickel-base superalloy Inconel 718 (IN718) is strengthened primarily by precipitation of two types of intermetallic phases in the austenite (γ) matrix: metastable γ' (cubic Ll2 structure) and γ" (tetragonal D022 structure) precipitates. Minor changes of the chemistry of the IN718 alloy can significantly affect its mechanical properties at high temperatures. It has been found that the microstructural stability of the precipitates and the high temperature performance of IN718 depend critically on the (Ti+Al)/Nb and Al/Ti ratios. The small sizes of these intermetallic phases and the fact that γ' precipitates are frequently associated with γ" precipitates in modified IN718 make it difficult to determine their composition. In this study, nanometer resolution analytical electron microscopy techniques have been used to characterize the structure, the morphology and the composition of the precipitated phases.The fabrication and the heat treatment of the modified IN718 alloy and its high temperature mechanical properties have been reported elsewhere.


2013 ◽  
Vol 675 ◽  
pp. 213-218
Author(s):  
Bin Fan ◽  
Ji Wen Fan

Laser shocking peening (LSP) is a good way to improving mechanical properties. The influence of laser shock peeening on the high temperature mechanical properties were studied by investigating the thermal stability of residual compressive stress induced by LSP and high temperature tensile properties. The samples treated by LSP were placed in annealing oven and insulated for 60mins under 200°C. The high temperature tensile tests were did on the MTS machine, the temperatures were 250°C. The results showed that the compressive residual stress induced by LSP were only released 19.7%, the residual compressive stress still remained at a high level, about-125.45MPa; the results from the high temperature tensile tests shows LSP can improved the elevated temperature tensile strength, the ultimate tensile strength(UTS) of LSP was from 319.79MPa to 252.63MPa,decreased 21%, but the UTS of untreated by LSP was from 283MPa to 130.18MPa,released 46.1%.


1990 ◽  
Vol 213 ◽  
Author(s):  
R. Wagner ◽  
M. Es-Souni ◽  
D. Chen ◽  
B. Dogan ◽  
J. Seeger ◽  
...  

ABSTRACTPrevious work has shown that ternary Ti-Al-Si alloys with hypoeutectic and eutectic microstructures containing the intermetallic phases Ti3 (Al,Si) and Ti5 (Si,Al)3 have promising high temperature mechanical properties [1]. In the present investigation alloying additions of Niobium have been made to selected Ti-Al-Si alloys based on hypoeutectic compositions and the effects of Niobium on the microstructure and mechanical properties have been studied. The high temperature creep and oxidation behaviour of such alloys appears to be superior to that of currently available Ti3Al-based alloys.


2011 ◽  
Vol 291-294 ◽  
pp. 565-568
Author(s):  
Zhong Zhao ◽  
Qiang Luo ◽  
Zi Tian Fan

The microstructures and mechanical properties of Mg9AlZnGdY alloy after T6 heat treatment in lost foam casting (LFC) are compared with that of AZ91D magnesium alloy. The results show that the microstructures of Mg9AlZnGdY alloy after T6 heat treatment consist of the α-Mg solid solution, β-Mg17Al12 precipitation phase, a small amount of rod Al2Y and block Al2Gd phases, which are distributed over grain boundaries of the α-Mg phase. The thermal stability of Al2Y and Al2Gd phases offers the pinning effect on the grain boundary under high temperature, and therefore, the grain boundary sliding is eliminated and the high-temperature strength is increased. After the T6 heat treatment, the tensile strength of Mg9AlZnGdY alloy was 235MPa at room temperature, and 156MPa at 200°C. Compared with that of AZ91D alloy, the tensile strength was increased by 19.3% and 38.1% respectively.


Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 980 ◽  
Author(s):  
Guohua Wu ◽  
H. Jafari Nodooshan ◽  
Xiaoqin Zeng ◽  
Wencai Liu ◽  
Dejiang Li ◽  
...  

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.


2013 ◽  
Vol 652-654 ◽  
pp. 1030-1034 ◽  
Author(s):  
Wen Da Zhang ◽  
Jing Yang ◽  
Jing Zhi Dang ◽  
Yun Liu ◽  
Hong Xu

The regression equation of the relationship between Si, Cu and Mg and the mechanical properties of Al-Si-Cu-Mg alloy was established according to the orthogonal experimental results. The microstructure of the Al-Si-Cu-Mg alloy was analyzed with scanning electron microscopy and energy dispersive spectroscopy. The results show that Si, Cu and Mg affected the mechanical properties (tensile strength and elongation rate) at 250 °C most significantly, minimally and negatively, respectively. The interactions between Cu, Mg and Si greatly reduced the high-temperature tensile strength owing to the formation of brittle and hard intermetallic Al5Mg8Cu2Si6 that behaved as the initial crack during stretching.


2012 ◽  
Vol 538-541 ◽  
pp. 1601-1604
Author(s):  
Xiao Liu ◽  
Jian She Li

The effects of Ce on the inclusions and the high temperature mechanical properties of 2Cr13 stainless steel were studied. The results show that the morphologies and sizes of inclusions in 2Cr13 stainless steel are changed, and Ce played a very good role of modifying inclusions. The high temperature strength of 2Cr13 stainless steel is improved obviously by Ce. In comparison with 2Cr13 stainless steel without Ce, the high temperature strength of 2Cr13 stainless steel with Ce is increased 18.18% at 1273K, respectively.


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