Mechanical Properties of a Novel High-Strength Aluminum-Lithium Alloy

2011 ◽  
Vol 689 ◽  
pp. 385-389 ◽  
Author(s):  
Zhi Shan Yuan ◽  
Zheng Lu ◽  
You Hua Xie ◽  
Xiu Liang Wu ◽  
Sheng Long Dai ◽  
...  

As a heat treatable aluminum alloy to be used in T6 and T8 temper, belongs to Al-Cu-Li system, a novel high-strength aluminum-lithium alloy 2A97 was developed. In order to improve the relationships of strength and ductility and fracture toughness, and to urge the applications in the aeronautical and aerospace industries, the effects of normal heat treatments and thermomechanical heat treatments on the mechanical properties and fracture toughness were investigated by Transmission Electron Microscope(TEM), Scanning Electronic Microscope (SEM), tensile test, and fracture toughness test. The results show that for the alloy aged at 135 °C for 24 h after quenching and 4 percent plastic deformation, its microstructures are strengthened by strain hardening and precipitation hardening, consisting of fine T1phase, θ″/θ′ phase and δ′ phase densely and homogeneously distributed in the matrix. It yields optimum relationship of strength and ductility, fracture toughness, its σ0.2, σband δ5are 454 MPa, 536 MPa, and 11.8%, respectively. It yields 43.5 MPa·m1/2of Kqvalues higher than that of 42.5 MPa·m1/2 in T6 temper. The fracture morphologies of impact tensile samples of fracture toughness test and normal tensile test were observed, indicating the dominance of intergranular failure and subintergranular failure with some dimples and trangranular failure.

2021 ◽  
Author(s):  
M. Saravana Kumar ◽  
E. Mohan ◽  
S. Robinson ◽  
D. ThivyaPrasad

Abstract Stir casting plays a major role in production of Al-SiC10% composites for aero space and automobile applications. However, obtaining the composites with homogenous distribution of the SiC particles, low porosity and without clustering of reinforcement particles were still a major problem faced by the research community. These kinds of casting defects were overcome by the Additive Manufacturing (AM) technology. In this research, AlSi10Mg parts were manufactured by Laser-Powder Bed Fusion (LPBF) method, one of the AM techniques. The mechanical and morphological characteristics of AM samples were compared with the Stir Casted (SC) samples. The influence of print orientation on the mechanical properties was also evaluated. It was found that the AM samples printed along the XY directions shows 26.5% and 8.2%higher fracture toughness and shear strength than AM samples printed along the Z directions. Both AM and SC samples were analyzed for the porosity% using the Optical Microscope (OM). The result shows that the AM sample shows reduced porosity of 1.4%. Mechanical testing such as tensile test, hardness test, fracture toughness test and double shear stress were carried out. The results obtained from the tensile test AM samples show 14.6% higher tensile strength than the SC samples, from the hardness test AM samples show 18.6% higher hardness strength than the SC samples, from the fracture toughness test AM samples show 33.4% higher fracture toughness strength than the SC samples and from the double shear stress test prove that the AM samples show 24.6% higher shear stress than the SC samples. The outcome of this research, it was proved that additive manufactured AlSi10Mgsample shows enhanced mechanical and morphological properties when compared with the conventional stir casting process.


Alloy Digest ◽  
2005 ◽  
Vol 54 (12) ◽  

Abstract The aluminum-lithium alloy 2099, also designated C460, was developed for use in aerospace and high-strength applications. The alloy has a lithium addition for lowered density compared to more conventional alloys. This datasheet provides information on composition, physical properties, tensile properties, and compressive strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming. Filing Code: AL-398. Producer or source: AEAP-Alcoa Engineered Aerospace Products.


2004 ◽  
Vol 449-452 ◽  
pp. 709-712
Author(s):  
Shoichi Nambu ◽  
Manabu Enoki

It was pointed out that one of the causes of recent failure to launch rocket was due to the fracture of nozzle throat insert made of graphite materials. The relationship between mechanical properties and microfracture process in graphite was not enough analyzed. To ensure the reliability of such aerospace equipment, we considered the necessity of assurance by non-destructive evaluation, evaluation of mechanical property for graphite material and design based on fracture probability. In this study, four-point bending test and fracture toughness test were used to evaluate mechanical properties. Mean strength, Weibull parameters, and R-curve for crack propagation were estimated. AE measurement during tests was performed in order to obtain location and stress of microfracture. AE results were analyzed by stochastic process theory. The result of AE demonstrates that microfracture process during bending test is divided into three stages. AE behavior in fracture toughness test was also closely related to crack propagation.


Author(s):  
D.M. Vanderwalker

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.


Alloy Digest ◽  
1994 ◽  
Vol 43 (11) ◽  

Abstract CARLSON ALLOYS C600 AND C600 ESR have excellent mechanical properties from sub-zero to elevated temperatures with excellent resistance to oxidation at high temperatures. It is a solid-solution alloy that can be hardened only by cold working. High strength at temperature is combined with good workability. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: Ni-470. Producer or source: G.O. Carlson Inc.


Alloy Digest ◽  
1958 ◽  
Vol 7 (1) ◽  

Abstract APEX 417 is an aluminum-magnesium casting alloy having high strength and ductility, excellent corrosion resistance and good dimensional stability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-61. Producer or source: Apex Smelting Company.


Alloy Digest ◽  
1986 ◽  
Vol 35 (5) ◽  

Abstract Copper Alloy No. C86100 is a copper-zinc-aluminum-manganese-iron alloy, sometimes classified as a high-strength yellow brass. The principal strengthening element is aluminum. Its tensile strength is typically 95,000 psi (655 MPa). It has a good combination of strength and ductility along with good resistance to corrosion. Its typical uses are marine castings, gears, gun mounts, bearing and bushings. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-510. Producer or source: Copper alloy foundries.


2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.


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