Toughness after Interrupted Quench

2006 ◽  
Vol 519-521 ◽  
pp. 1017-1022 ◽  
Author(s):  
R.T. Shuey ◽  
Murat Tiryakioğlu ◽  
Gary H. Bray ◽  
James T. Staley
Keyword(s):  
Fracture Toughness ◽  
Aluminum Alloys ◽  
Yield Strength ◽  
Hold Time ◽  
Age Hardening ◽  
Quantitative Modeling ◽  
Nonlinear Relation ◽  
Strength And Toughness

We discuss data from a range of heat-treatable aluminum alloys, showing both yield strength and fracture toughness vs time at temperature of interrupted quench. Drop in toughness occurs at much shorter hold time than drop in strength. Concurrently the fracture becomes more intergranular. When later the yield strength falls, fracture becomes more transgranular, and toughness may rise. We attribute this pattern to two mechanisms: 1) Early quench precipitates nucleated on grain and/or subgrain boundaries grow to size sufficient to initiate fracture under tension, long before they withdraw significant solute from subsequent age-hardening. 2) Later quench precipitates nucleated on dispersoids and/or dislocations withdraw solute relatively uniformly, reducing matrix yield strength while increasing matrix ductility. We propose that quantitative modeling of change in strength and toughness with change in quench, requires multiple C-curves for multiple types of quench precipitates, and nonlinear relation of toughness to amount of boundary quench precipitate.

Effects of Post Weld Heat Treatments (PWHT) on Friction Stir Welded AA2219-T87 Joints

2017 ◽  
Author(s):  
Mohammad W. Dewan ◽  
Muhammad A. Wahab ◽  
Khurshida Sharmin
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Yield Strength ◽  
Solution Treatment ◽  
Welding Process ◽  
Alloying Elements ◽  
Age Hardening ◽  
Experimental Program ◽  
Friction Stir ◽  
Aging Period

Friction Stir Welding (FSW) offers significantly better performance on aluminum alloy joints compared to the conventional fusion arc welding techniques; however, plastic deformation, visco-plastic flow of metals, and complex non-uniform heating cycles during FSW processes, result in dissolution of alloying elements, intrinsic microstructural changes, and post-weld residual stress development. As a consequence, about 30% reduction in ultimate strength (UTS) and 60% reduction in yield strength (YS) were observed in defect-free, as-welded AA2219-T87 joints. PWHT is a common practice to refine grain-coarsened microstructures which removes or redistributes post-weld residual stresses; and improves mechanical properties of heat-treatable welded aluminum alloys by precipitation hardening. An extensive experimental program was undertaken on PWHT of FS-welded AA2219-T87 to obtain optimum PWHT conditions and improvement of the tensile properties. Artificial age-hardening (AH) helped in the precipitation of supersaturated alloying elements produced around weld nugget area during the welding process. As a result, an average 20% improvement in YS and 5% improvements in UTS was observed in age-hardened (AH-170°C-18h) specimens as compared to AW specimens. To achieve full benefit of PWHT, solution-treatment followed by age-hardening (STAH) was performed on FS-welded AA2219-T87 specimens. Solution-treatment (ST) helps in the grain refinement and formation of supersaturated precipitates in aluminum alloys. Age-hardening of ST specimens help in the precipitation of alloying elements around grain boundaries and strengthen the specimens. Optimum aging period is important to achieve better mechanical properties. For FS-welded AA2219-T87 peak aging time was 5 hours at 170°C. STAH-170°C -5h treated specimens showed about 78% JE based on UTS, 61% JE based on yield strength, and 36% JE based on tensile toughness values of base metal.

Yield Strength Prediction for Rapid Age-Hardening Heat Treatment of Aluminum Alloys

2013 ◽  
pp. 87-94
Author(s):  
Hebi Yin ◽  
Adrian S. Sabau ◽  
Gerard M. Ludtka ◽  
Timothy W. Skszek ◽  
Xiaoping Niu
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Yield Strength ◽  
Age Hardening ◽  
Strength Prediction ◽  
Hardening Heat Treatment

Plane-Strain Fracture Toughness of High-Strength Aluminum Alloys

1965 ◽  
Vol 87 (4) ◽  
pp. 904-916 ◽  
Author(s):  
C. M. Carman ◽  
D. F. Armiento ◽  
H. Markus
Keyword(s):  
Fracture Toughness ◽  
Aluminum Alloys ◽  
Yield Strength ◽  
Plane Strain ◽  
Process Zone ◽  
Inverse Function ◽  
High Strength ◽  
Plane Strain Fracture Toughness ◽  
Strain Fracture ◽  
Impurity Elements

The plane-strain fracture toughness of precipitation-hardening aluminum alloys of 7000 and 2000 series and a strain-hardening alloy 5456 have been determined at both room temperature and −320 F using circumferentially notched rounds. These results show that the plane-strain fracture toughness is an inverse function of the yield strength and that at equivalent yield-strength levels the 7000 series of alloys is tougher than the 2000 series of alloys. Plane strain-fracture toughness values were determined using “pop-in” technique employing both the center crack and single-edge-notch specimens. Comparable values were obtained in all examples tested. The effects of impurity elements, iron and silicon, on the fracture toughness of 7075-T6 aluminum alloy were investigated using a special low iron-and-silicon melt of 7075-T6 material. Reduction of these impurity elements resulted in a 30 to 45 percent upgrading of the plane-strain fracture toughness of this alloy. These data have been interpreted in terms of the process zone size, dT, using electron microfractography as an indication of this parameter. The plane strain-fracture toughness values have been used to calculate the breaking stress of part-through-cracked panel. These calculations have been confirmed experimentally for two alloys. Such data have direct applicability in the design of structures.

New Light-Weight Aluminium Alloys with High Mg2Si-Content by Spray Forming

2006 ◽  
Vol 519-521 ◽  
pp. 1245-1250 ◽  
Author(s):  
O. Stelling ◽  
A. Irretier ◽  
O. Kessler ◽  
P. Krug ◽  
Bernd Commandeur
Keyword(s):  
Aluminum Alloys ◽  
Yield Strength ◽  
Solidification Rate ◽  
Physical And Mechanical Properties ◽  
Spray Forming ◽  
Age Hardening ◽  
Light Weight ◽  
Fine Microstructure ◽  
Si Content ◽  
Compact Design

Aluminum alloys with high Mg2Si-content (>10 %) offer the possibility of a significant decrease in density and an increase in stiffness at the same time. But these alloys can hardly be produced in casting processes, due to an oxidation and a generation of pores by hydrogen solubility of the melt. Furthermore, the usual solidification rate is not sufficient for a fine microstructure morphology. A fine distribution of Mg2Si is possible by spray forming, where a coarsening of the particles can be avoided due to a higher solidification rate. Different aluminum alloys with high Mg2Si-content (>10 %) have successfully been produced by spray forming, extrusion and age hardening. Mg-excess as well as Si-excess has been investigated. An additional alloying with copper leads to a further increase in strength by the precipitation sequence of Al2Cu. The new light-weight aluminum alloys have been investigated regarding age hardening, physical and mechanical properties. Densities of 2.5-2.6 g/cm3 and Young´s modulus of approx. 80,000 MPa have been found. Microstructures were dense, homogeneous and of fine morphology. The yield strength of these alloys reached values of approx. 400 MPa after artificial aging, whereby only a slight decrease for the hot yield strength was observed up to a temperature of 200 °C. Applications of the new light-weight aluminum alloys can be expected where a reduced density together with a high hot yield strength would lead to a more compact design in high temperature environments, e.g. in combustion engines.

ATI S240

Alloy Digest ◽  
2011 ◽  
Vol 60 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Martensitic Stainless Steel ◽  
Heat Treating ◽  
Age Hardening ◽  
Strength And Toughness

Abstract ATI S240 is an age-hardening martensitic stainless steel with strength and toughness comparable to other commercial steels in the class, but with improvements. The 240 in the title is the tensile strength. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1107. Producer or source: ATI Allvac.

REPUBLIC RSM-300

Alloy Digest ◽  
1969 ◽  
Vol 18 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Yield Strength ◽  
High Strength ◽  
Heat Treating ◽  
Age Hardening ◽  
Extrusion Dies ◽  
Temperature Performance ◽  
Nickel Cobalt

Abstract Republic RSM-300 alloy is an 18% nickel-cobalt-molybdenum age-hardening steel designed to develop up to 300,000 psi yield strength with good toughness. It is recommended for landing gears extrusion dies, rocket motor cases, high-strength bolts, etc. 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 low and high temperature performance, and corrosion resistance as well as heat treating, machining, joining, and surface treatment. Filing Code: SA-242. Producer or source: Republic Steel Corporation.

COPPER ALLOY No. 182

Alloy Digest ◽  
1975 ◽  
Vol 24 (12) ◽  
Keyword(s):  
Electrical Conductivity ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Copper Alloy ◽  
Heat Treating ◽  
Age Hardening ◽  
High Electrical Conductivity ◽  
Temperature Performance

Abstract Copper Alloy NO. 182 is an age-hardening type of alloy that combines relatively high electrical conductivity with good strength and hardness. It was formerly known as Chromium Copper and its applications include such uses as resistance-welding-machine electrodes, switch contacts and cable connectors. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-305. Producer or source: Copper and copper alloy mills.

VALLOUREC VM 85 13Cr

Alloy Digest ◽  
2016 ◽  
Vol 65 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Alloy Carbon ◽  
Sour Service ◽  
Minimum Yield

Abstract Vallourec VM 85 13Cr (minimum yield strength 85 ksi, or 586 MPa) is a low alloy carbon steel for use in oil country tubular goods as a material suitable for sour service. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: CS-198. Producer or source: Vallourec USA Corporation.

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