The Effect of Microalloying of Nickel, RRA Treatment on Microstructure and Mechanical Properties for High Strength Aluminum Alloy

2014 ◽  
Vol 925 ◽  
pp. 253-257 ◽  
Author(s):  
Haider T. Naeem ◽  
Kahtan S. Mohammad ◽  
Khairel R. Ahmad

High strength aluminum alloys Al-Zn-Mg-Cu-(0.1) Ni produced by semi-direct chill casting process were homogenized at different conditions then conducted heat treatment process which comprised pre-aging at 120°C for 24 h, retrogression at 180°C for 30 min, and then re-aging at 120°C for 24 h. Microstructural studies showed that add Ni (0.1 wt %) to the alloy will be forming Ni-rich phases such as AlCuNi, AlNi, AlNiFe and AlMgNi which provide a dispersive strengthening affected in the solid-solution and the subsequent heat treatments. The results showed that by this three-step process of heat treatments, the mechanical properties of aluminum alloys Al-Zn-Mg-Cu-(0.1) Ni were substantially improved. The highest attain for the ultimate tensile strength and Vickers hardness for the alloy sample after applied the retrogression and reaging process is about 545 MPa and 237 HV respectively.

2016 ◽  
Vol 877 ◽  
pp. 9-14
Author(s):  
Xing Han ◽  
Jian Zhong Cui

AA4045/AA3003 cladding billets with different clad ratios were fabricated by direct chill casting process. The macrostructures, microstructures, compositions distribution and the mechanical properties near the bonding interface were investigated in detail. The results show that the cladding billet with few defects could be obtained by semi-continuous casting process. The metallurgical bonding was formed due to the diffusions of elements. The decreasing of clad ratio changed the microstructure at the interface and reduced the thickness of diffusion layer. The hardness around the interface is higher than that of AA3003 side but lower than that of the other side, indicating that the interface yield strength is also higher than that of AA3003. After extrusion process, the characteristics of the interface remain that of as-cast cladding billet.


2020 ◽  
Vol 110 (10) ◽  
pp. 697-703
Author(s):  
Janosch Günzel ◽  
Timon Suckow ◽  
Ciarán-Victor Veitenheimer ◽  
Joachim Hauß ◽  
Peter Groche

Aufgrund ihrer geringen Kaltumformbarkeit werden hochfeste Aluminiumlegierungen in temperaturunterstützten Prozessrouten umgeformt. Bei mehrstufigen Prozessen führt dies zu komplexen und störanfälligen Prozessfolgen. Eine Umformung im W-Temper-Zustand vereinfacht die Temperaturführung und steigert die Robustheit. Die hierbei möglichen Prozessführungen sowie die Einflüsse der relevanten Prozessparameter (Zeit und Abschreckmethode) sind Inhalt dieses Beitrags.   Due to their low cold formability, high-strength aluminum alloys are formed in temperature-supported process routes. This leads to complex and failure-prone process sequences in multi-stage processes. Forming in the W-Temper state simplifies temperature control and increases robustness. This paper deals with the possible process control as well as the influences of the relevant process parameters (time and quenching method).


2009 ◽  
Vol 628-629 ◽  
pp. 477-482 ◽  
Author(s):  
Hong Min Guo ◽  
Xiang Jie Yang ◽  
J.X. Wang

Rheoforming is becoming the choice of the casting industry which relies on the semi-solid slurry for high integrity structural parts. The potential of rheoforming with LSPSF (Low superheat pouring with a shear field) for aluminum alloys was investigated in the present work. High quality semi-solid slurries of a series of aluminum alloys were manufactured by LSPSF process, such as casting alloy A356, high strength alloy 201, secondary die casting alloy A380 and wrought alloy 2024, 6082 and 7075, in which the primary α-Al presented spherical, small and homogeneous distribution, especially with zero-entrapped liquid. Applications of LSPSF in high pressure die casting process and squeeze casting process were presented. Results showed that LSPSF rheoforming could improve microstructures and increase mechanical properties.


2014 ◽  
Vol 925 ◽  
pp. 258-262 ◽  
Author(s):  
Haider T. Naeem ◽  
Khairul R. Ahmad ◽  
Kahtan S. Mohammad ◽  
Azmi Rahmat

In this study the evolution of the retrogression and reaging (RRA) heat treatment process on microstructure and mechanical properties of AA 7075 Al-alloys which produced by semi-direct chill (DC) casting process were investigated. Al-Zn-Mg-Cu alloys were homogenized at different heat treatment conditions, aged at 120°C for 24 h (T6), and retrogressed at 180°C for 30 min then re-aged at 120°C for 24 h (RRA). The results showed that this three-step process of the heat treatments, the mechanical properties of alloys was substantially improved. The highest ultimate tensile strength and Vickers hardness attained for the retrogression and re-aging about 530 MPa and 223 HV respectively. The precipitation strengthening is responsible about improve the strength under impact the retrogression and re-aging process.


Author(s):  
Vasile Hotea ◽  

In this work, some aspects of nondestructive testing methods has been highlighted out, from need to better understand the surface defects in the casting process of high strength aluminum alloy semifinished products used in aeronautical technique and how to apply the methods of nondestructive in general and, in particular, the method of penetrant liquid testing.


2010 ◽  
Vol 638-642 ◽  
pp. 1541-1545 ◽  
Author(s):  
Yuichi Ienaga

In order to realize large-scale Mg-Zn-Y alloys with high strength and high heat resistance, we have developed a unique casting process to produce a large homogeneous ingot investigating the mechanical properties of the extruded alloys. First homogeneous ingots (335 mm x 850 mm) were prepared by a unique stir casting process. Then large-scale extruded alloys (100 mm) were prepared at 648 K with the extrusion ratio of 10. The Mg-Zn-Y alloys have exhibited higher yield and fatigue strengths than those of aluminum alloys. The yield strengths of the aluminum alloys have decreased drastically above 473 K, whereas those of the Mg-Zn-Y alloys have not. It is noteworthy that the yield strength (200 MPa) and the fatigue strength (75 MPa) of the Mg-Zn-Y alloys at 523 K are about twice and 1.2-1.4 times as high as those of the aluminum alloys respectively. Moreover, the creep strengths have been equivalent or higher than those of aluminum alloys. From the above results, we have verified that even being made by the large-scale extrusion, the Mg-Zn-Y alloys possess higher strength than those of heat resistant aluminum alloys.


2007 ◽  
Vol 561-565 ◽  
pp. 995-998 ◽  
Author(s):  
Dmitry G. Eskin ◽  
Laurens Katgerman

Hot tearing is a significant problem upon direct-chill casting of high-strength aluminum alloys. The occurrence of hot cracks is related to the thermal contraction of the solid phase and to the lack of feeding by the liquid phase during solidification. It has been identified that structure features such as grain size and amount of nonequilibrium eutectics influence both phenomena involved in hot tearing. Experimental and computer-simulation results are presented for a range of model and commercial aluminum alloys. The results are obtained both during special small-scale experiments and during industrial-scale direct-chill casting. It is shown that grain refinement reduces hot tearing susceptibility of aluminum alloys through the related decrease of the temperature of thermal contraction onset and increased permeability of the mushy zone. The effects of process parameters on hot tearing are also discussed.


2019 ◽  
Vol 969 ◽  
pp. 546-551
Author(s):  
J. Suresh Kumar ◽  
M. Siva ◽  
N. Suneel Kumar ◽  
CH.V.V.S.S.R Krishna Murthy ◽  
V.V. Ravi Kumar

High strength aluminum alloys will enhancing mechanical properties always plays a major role in controlling microstructure of cast and processed alloy. The desire for more efficient aircraft materials has fueled research of aluminum AA-2xxx and AA7xxx alloys. In these alloys were rolled at cold rolling and at cryorolling to 80 % thickness reductions and an attempt was made to evaluate the optical-microstructural variation and the variation in tensile properties of these aluminum alloys. Cryorolled alloy also exhibited better hardness and strength compared to cold alloy due to suppressed thermal recovery. Coldrolled alloy showed more necking percentage compared to cryorolled for rolling reductions of 80% and more formability was observed.


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