Influence of Dissolved Precipitated Phases on Mechanical Properties of Severely Deformed Al-4 Wt% Cu Alloys

2010 ◽  
Vol 667-669 ◽  
pp. 1021-1026 ◽  
Author(s):  
Nan Hu ◽  
Xiao Chang Xu

Microstructural evolution and mechanical properties of Al-4.11 wt% Cu alloys subjected to multi-axial compression (MAC) and subsequent annealing were investigated. To clarify the influence of precipitated phases on mechanical properties, special samples containing only one kind of precipitated phase were prepared. During MAC at room temperature, θ"-phase-contained and θ′-phase-contained samples simultaneously showed increased strength and ductility as a function of MAC passes. This was ascribed to the considerable dissolution of precipitated phases induced by MAC that formed a supersaturated solid solution. In subsequent annealing at 393 K for 1 h, new precipitated phases appeared and the strength and ductility of deformed samples increased as precipitation proceeded. Additionally, transmission electron microscopy indicated that the MAC process accelerated the phase precipitations. Annealed mechanical properties were a function of MAC passes, annealing time, and temperature. In this study, an optimum comprehensive mechanical property was achieved in the θ"-phase-contained specimen, after eight passes of MAC and 1 h annealing at 393 K.

2019 ◽  
Vol 11 (11) ◽  
pp. 1489-1501
Author(s):  
Wenjing He ◽  
Caihe Fan ◽  
Shu Wang ◽  
Junhong Wang ◽  
Su Chen ◽  
...  

The evolution of nanoprecipitated phases in Al–Cu alloys under severe plastic deformation (SPD) is summarized in this study. SPD at room temperature induces the precipitation of Al–Cu alloys to dissolve, leading to the reformation of supersaturated solid solution in the aluminum matrix. In the process of SPD or aging treatment after the SPD, the reprecipitated phases are precipitated from the aluminum matrix and the mechanical properties of the alloys are remarkably improved. The mechanism and system of the redissolution of the precipitation phases and the effects of redissolution and reprecipitation on the microstructure and properties of Al–Cu alloys are comprehensively analyzed. The development and future of redissolution and reprecipitation of nanoprecipitated phases in Al–Cu alloys are also described.


2007 ◽  
Vol 23 ◽  
pp. 123-126
Author(s):  
Radu L. Orban ◽  
Mariana Lucaci

This paper investigates the effect of Fe, Cr and B additions, in small proportions, as alloying elements in Ni3Al with the purpose to reduce its intrinsic fragility and extrinsic embrittlement and to enhance, in the same time, its mechanical properties. It represents a development of some previous research works of the authors, proving that Ni3Al-Fe-Cr-B alloys obtained by reactive synthesis (SHS) starting from Mechanically Alloyed powder mixtures have superior both room temperature tensile strength and ductility, and compression ones at temperatures up to 800 °C, than pure Ni3Al. These create premises for their using as superalloys substitutes.


2000 ◽  
Vol 6 (S2) ◽  
pp. 768-769
Author(s):  
O. A. Hilders ◽  
A. Quintero ◽  
L. Berrio ◽  
R. Caballero ◽  
L. Sáenz ◽  
...  

There have been several attempts to find a relation between the fractal morphology of the fracture surfaces and the mechanical properties of engineering materials., although the current resuls are inconclusive. If there are correlations between the fractal dimension and such properties, this parameter could be very useful to predict them and to improve the resistance to fracture. The main part of the investigations concerned with the fractal geometry and fracture behavior concentrate on the relations between roughness and fracture toughness . In the present work, the effects of thermal aging at 850°C on the fracture topography developed during the rupture in tension at room temperature of a 304 type stainless steel and their relation with the strength and ductility, were studied using the fractal geometry approach.


2010 ◽  
Vol 667-669 ◽  
pp. 731-736 ◽  
Author(s):  
Irina P. Semenova ◽  
Alexander Medvedev

This work presents the possibility of strength enhancement in the -alloy Ti-6.8Mo-4.5Fe-1.5Al via equal channel angular pressing at room temperature without precipitation of a secondary -phase. Influence of the initial structure of the alloy and ageing temperature on the density of precipitations and dimensions of the secondary -phase is revealed. It has been stated that combination of the solid solution treatment with the subsequent ECAP processing and final ageing is an effective way to achieve superior strength and ductility.


2010 ◽  
Vol 638-642 ◽  
pp. 3128-3133 ◽  
Author(s):  
Felix Peñalba ◽  
Xabier Gómez ◽  
R. Allende ◽  
Manuel Carsí ◽  
Oscar A. Ruano

The possibilities to improve the properties of steels for tubes exposed at high temperatures are explored. The mechanical properties and forming behavior of an experimental casting of type 9Cr-ferritic steels, P92, containing 2%W, are studied. The hardenability was determined by means of continuous cooling diagrams associated with hardness measurements and microstructure observations. Tensile tests from room temperature to 650°C were carried out to determine the variation of the strength and ductility in this temperature range. In addition, Charpy impact tests were conducted to characterize the toughness of the steel and the ductile-brittle transition temperature. Finally, hot torsion tests at various temperatures and strain rates were carried out and the generalized stresses and strains to rupture for each test are determined. With these data forming stability maps were generated to characterize the best forming conditions.


2015 ◽  
Vol 816 ◽  
pp. 48-53
Author(s):  
Jing Zhang ◽  
Hua Shun Yu ◽  
Xin Ting Shuai ◽  
Hong Mei Chen ◽  
Guang Hui Min

Al2O3 particles reinforced ZL109 composites were prepared by in-situ reaction between Fe2O3+MnO2 and Al in this paper. The influence of ratio of Mn to Fe on the morphologies of Al-Si-Mn-Fe phase and mechanical properties of the composites was investigated. The microstructure was studied by electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM). The results show that the Al2O3 particles displaced by the Fe2O3+MnO2/Al system are in nanosize. The acicular Al-Si-Fe phases change from acicular to polygonal shape and become smaller with the increase manganese content. The hardness test results have no big difference on the composites. However, the ultimate tensile strength at room temperature and 350°C enhance evidently with the increasing of Mn/Fe.


2012 ◽  
Vol 476-478 ◽  
pp. 29-33
Author(s):  
Shao Ding Sheng ◽  
Hong Ge Yan

AZ91 alloy powder was prepared by two-roller quenching equipment. The powders were consolidated and extruded into bar. The microstructures of the powders and bars were observed by optical microscope (OM), XRD, HRTEM and SEM. The results suggested that the grain size of the powder were equiaxed with the sizes of about 1~5μm. The as-extruded alloy bars retain equiaxed grains with a large number of precipitated phases, β-Al12Mg17 and AlMg2Zn. The alloy exhibited excellent mechanical properties, the ultimate and yield tensile strength were 383.2MPa and 275.1MPa respectively. The shape of the precipitated phase was approximately globular with the size of about 50~200nm.


Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 913 ◽  
Author(s):  
Lehang Ma ◽  
Jianguo Tang ◽  
Wenbin Tu ◽  
Lingying Ye ◽  
Haichun Jiang ◽  
...  

In this paper, the effect of trace Sn on the precipitation behavior and mechanical properties of Al–Mg–Si alloys with different Mg/Si ratios aged at 180 °C was investigated using hardness measurements, a room-temperature tensile test, transmission electron microscopy and differential scanning calorimetry. The results shown that Sn reduces the precipitation activation energy, increases the number density of β″ precipitates, and then increased the aging hardenability and mechanical properties of the Al–Mg–Si alloy. However, the positive effect of Sn on the mechanical properties of the Al–Mg–Si alloy drops with the decrease of the Mg/Si ratio of the alloy.


2021 ◽  
Vol 1016 ◽  
pp. 917-921
Author(s):  
Haruka Miyano ◽  
Keisuke Takemoto ◽  
Hiromoto Kitahara ◽  
Shinji Ando

In this study, tensile tests of rolled Mg-Li alloy and Mg-Ce alloy sheets were carried out at room temperature to investigate effects of alloying additions on the relationship between mechanical properties and activities of slip systems in magnesium polycrystals. In Mg-Li alloy, ductility increased while strength decreased by lithium addition. Frequency of non-basal slips increased with increasing lithium content. In Mg-Ce alloy, strength and ductility were similar pure magnesium, and non-basal slips were hardly activated. Since critical resolved shear stress of non-basal slips were decreased by lithium addition, ductility of magnesium was increased while its strength was decreased.


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