scholarly journals Soil load support capacity increases with time without soil mobilization as a result of age-hardening phenomenon

2019 ◽  
Vol 186 ◽  
pp. 128-134 ◽  
Author(s):  
Moacir Tuzzin de Moraes ◽  
Felipe Bonini da Luz ◽  
Henrique Debiasi ◽  
Julio Cezar Franchini ◽  
Vanderlei Rodrigues da Silva
Keyword(s):  
Author(s):  
J. E. O'Neal ◽  
K. K. Sankaran

Al-Li-Cu alloys combine high specific strength and high specific modulus and are potential candidates for aircraft structural applications. As part of an effort to optimize Al-Li-Cu alloys for specific applications, precipitation in these alloys was studied for a range of compositions, and the mechanical behavior was correlated with the microstructures.Alloys with nominal compositions of Al-4Cu-2Li-0.2Zr, Al-2.5Cu-2.5Li-0.2Zr, and Al-l.5Cu-2.5Li-0.5Mn were argon-atomized into powder at solidification rates ≈ 103°C/s. Powders were consolidated into bar stock by vacuum pressing and extruding at 400°C. Alloy specimens were solution annealed at 530°C and aged at temperatures up to 250°C, and the resultant precipitation was studied by transmission electron microscopy (TEM).The low-temperature (≲100°C) precipitation behavior of the Al-4Cu-2Li-0.2Zr alloy is a combination of the separate precipitation behaviors of Al-Cu and Al-Li alloys. The age-hardening behavior at these temperatures is characteristic of Guinier-Preston (GP) zone formation, with additional strengthening resulting from the coherent precipitation of δ’ (Al3Li, Ll2 structure), the presence of which is revealed by the selected-area diffraction pattern (SADP) shown in Figure la.


Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.


Author(s):  
M.J. Witcomb ◽  
U. Dahmen ◽  
K.H. Westmacott

Cu-Cr age-hardening alloys are of interest as a model system for the investigation of fcc/bcc interface structures. Several past studies have investigated the morphology and interface structure of Cr precipitates in a Cu matrix (1-3) and good success has been achieved in understanding the crystallography and strain contrast of small needle-shaped precipitates. The present study investigates the effect of small amounts of phosphorous on the precipitation behavior of Cu-Cr alloys.The same Cu-0.3% Cr alloy as was used in earlier work was rolled to a thickness of 150 μm, solution treated in vacuum at 1050°C for 1h followed by quenching and annealing for various times at 820 and 863°C.Two laths and their corresponding diffraction patterns in an alloy aged 2h at 820°C are shown in correct relative orientation in Fig. 1. To within the limit of accuracy of the diffraction patterns the orientation relationship was that of Kurdjumov-Sachs (KS), i.e. parallel close-packed planes and directions.


Author(s):  
F. J. Fraikor ◽  
A. W. Brewer

A number of investigators have examined moire patterns on precipitate particles in various age-hardening alloys. For example, Phillips has analyzed moire fringes at cobalt precipitates in copper and Von Heimendahl has reported on moire fringes in the system Al-Au. Recently, we have observed moire patterns on impurity precipitates in beryllium quenched in brine from 1000°C and aged at various temperatures in the range of 500-800°C. This heat treatment of beryllium rolled from vacuum cast ingots produces the precipitation of both an fee ternary phase, AlFeBe4, and an hcp binary phase, FeBe11. However, unlike a typical age-hardening alloy, the solute content of this material is low (less than 1000 ppm of Fe and 600 ppm of Al) and hence the total volume fraction of precipitates is small. Therefore there is some difficulty in distinguishing the precipitates and their orientation relationships with the beryllium matrix since the weak precipitate spots generally do not appear on the diffraction patterns.


Author(s):  
M. Tamizifar ◽  
G. Cliff ◽  
R.W. Devenish ◽  
G.W. Lorimer

Small additions of copper, <1 wt%, have a pronounced effect on the ageing response of Al-Mg-Si alloys. The object of the present investigation was to study the effect of additions of copper up to 0.5 wt% on the ageing response of a series of Al-Mg-Si alloys and to use high resolution analytical electron microscopy to determine the composition of the age hardening precipitates.The composition of the alloys investigated is given in Table 1. The alloys were heat treated in an argon atmosphere for 30m, water quenched and immediately aged either at 180°C for 15 h or given a duplex treatment of 180°C for 15 h followed by 350°C for 2 h2. The double-ageing treatment was similar to that carried out by Dumolt et al. Analyses of the precipitation were carried out with a HB 501 Scanning Transmission Electron Microscope. X-ray peak integrals were converted into weight fractions using the ratio technique of Cliff and Lorimer.


Alloy Digest ◽  
2000 ◽  
Vol 49 (10) ◽  

Abstract CMW 100 is a copper alloy that combines high tensile strength with high electrical and thermal conductivity. It responds to age-hardening heat treatment. It is used for flash welding dies, springs, electrical components, high-strength backing material for brazed assemblies, and wire guides. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-29. Producer or source: CMW Inc. Originally published as Mallory 100, August 1955, revised October 2000.


Alloy Digest ◽  
1953 ◽  
Vol 2 (10) ◽  

Abstract CONDULOY is a low beryllium-copper alloy containing about 1.5% nickel. It responds to age-hardening heat treatment for improved mechanical properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on casting, heat treating, machining, and joining. Filing Code: Cu-11. Producer or source: Brush Beryllium Company.


Alloy Digest ◽  
1987 ◽  
Vol 36 (12) ◽  

Abstract UNS No. A02060 is an aluminum-mold casting alloy that responds to an age-hardening heat treatment. It is recommended for applications that require a combination of high tensile properties and good machinability. Among its many uses are fuel pump bodies, aircraft fittings and seat frames for railway passenger cars. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on high temperature performance as well as casting, heat treating, machining, and joining. Filing Code: Al-285. Producer or source: Various aluminum companies.


Alloy Digest ◽  
1965 ◽  
Vol 14 (4) ◽  

Abstract INCONEL Alloy 722, formerly Inconel W alloy, is a high strength, high-temperature nickel-base alloy responding to age hardening heat treatments for maximum properties. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-100. Producer or source: Huntington Alloy Products Division, An INCO Company.


Alloy Digest ◽  
2006 ◽  
Vol 55 (1) ◽  

Abstract Brush Wellman Q-Max tube is a high-strength age-hardening copper alloy with excellent biological resistance for use in waters as condenser tubing. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: CU-739. Producer or source: Brush Wellman Inc.


Sign in / Sign up

Export Citation Format

Share Document