scholarly journals Microstructural Change during the Interrupted Quenching of the AlZnMg(Cu) Alloy AA7050

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2554 ◽  
Author(s):  
Thomas M. Kremmer ◽  
Phillip Dumitraschkewitz ◽  
Daniel Pöschmann ◽  
Thomas Ebner ◽  
Peter J. Uggowitzer ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Phase Distribution ◽  
Atom Probe ◽  
Industrial Applications ◽  
Treatment Temperature ◽  
Strength Increase ◽  
Artificial Ageing ◽  
Cu Alloy

This study reports on the effect of interrupted quenching on the microstructure and mechanical properties of plates made of the AlZnMg(Cu) alloy AA7050. Rapid cooling from the solution heat treatment temperature is interrupted at temperatures between 100 and 200 °C and continued with a very slow further cooling to room temperature. The final material’s condition is achieved without or with subsequent artificial ageing. The results show that an improvement in the strength–toughness trade-off can be obtained by using this method. Interrupted quenching at 125 °C with peak artificial ageing leads to a yield strength increase of 27 MPa (538 MPa to 565 MPa) compared to the reference material at the same fracture toughness level. A further special case is the complete omission of an artificial ageing treatment with interrupted quenching at 200 °C. This heat treatment exhibits an 20% increase in fracture toughness (35 to 42 MPa m−1/2) while retaining a sufficient yield strength of 512 MPa for industrial applications. A detailed characterization of the relevant microstructural parameters like present phases, phase distribution and precipitate-free zones is performed using transmission electron microscopy and atom probe tomography.

scholarly journals The Effect of Elastic Strain and Small Plastic Deformation on Tensile Strength of a Lean Al–Mg–Si Alloy

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1276
Author(s):  
Eva Anne Mørtsell ◽  
Ida Westermann ◽  
Calin Daniel Marioara ◽  
Ketill Olav Pedersen ◽  
Sigmund Jarle Andersen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Plastic Deformation ◽  
Elastic Strain ◽  
Solution Heat Treatment ◽  
Small Deformation ◽  
Age Hardening ◽  
Strength Increase ◽  
Artificial Ageing ◽  
Small Plastic ◽  
Small Plastic Deformation

Al–Mg–Si alloys are usually formed into their final shape by rolling or extrusion. After extrusion, the aluminium profiles are usually straightened, causing the material to be subjected to a small plastic deformation. This study demonstrates the positive effect on strength that can be obtained from such small deformation levels or from only elastically straining the material. Elastic straining of a lean Al–Mg–Si alloy, when performed immediately after solution heat treatment, enhances the material yield strength after artificial ageing to T6. Transmission electron microscopy shows that this effect can be attributed to a higher number density and finer dispersion of the age-hardening precipitate needles. Furthermore, introducing a small plastic deformation of 1% after solution heat treatment results in a comparable strength increase to elastically straining the material. In this case, however, the strength increase is due to the increased dislocation density, which compensates for a lower density of precipitate needles. Finally, by combining plastic deformation with a succeeding elastic strain, we demonstrate how elastic strain can cause an on-set of dislocation cell formation in this material.

Effects of Natural Ageing on T6 Heat Treated Rheocasts of 319S Aluminum Alloy

2016 ◽  
Vol 256 ◽  
pp. 58-62 ◽  
Author(s):  
Kang Du ◽  
Qiang Zhu ◽  
Da Quan Li
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminium Alloys ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Treatment Temperature ◽  
Artificial Ageing ◽  
Natural Ageing ◽  
T6 Heat Treatment ◽  
Semi Solid

T6 heat treatment is an effective method to improve the comprehensive properties of Al-Si-Cu-Mg series aluminium alloys. Solution treatment temperature and time, quench process and media, as well as artificial ageing temperature and time are the key factors to determine mechanical properties. Besides these factors, natural ageing, i.e. the holding time between quenching and the starting of artificial treatment at ambient temperature was observed to be significant affect mechanical properties of the aluminium alloys. This effect on semi solid processed aluminium alloys was lack of investigations as the semi solid process produces T6 treatable and weldable components. The present paper focuses on the change regularity of hardness and precipitate behaviour of semi-solid 319S aluminium alloy under different natural ageing (NA) treatment additional to standard T6. Density and morphology of hardening precipitates are analysed using TEM, and the influence mechanism of NA during T6 heat treatment will be discussed. The results show that NA has a positive influence on mechanical properties of the rheo-cast 319S alloy.

Effects of a Thermal Coating Process on X100 UOE Line Pipe

2005 ◽  
Author(s):  
Chris Timms ◽  
Duane DeGeer ◽  
Martin McLamb
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Room Temperature ◽  
High Strength ◽  
Economic Benefits ◽  
Slight Reduction ◽  
Strength Increase ◽  
Coating Process ◽  
Line Pipe ◽  
Heat Treated

The increased demand for high strength linepipe for onshore and offshore pipeline systems has been well documented over the past few years. The economic benefits have been demonstrated, and solutions have been developed to address the technical issues facing high strength linepipe use. However, there are still a few unanswered questions, one of which is addressed in this paper: what is the effect of thermal treatment during the pipeline coating process on the material behaviour of high strength linepipe? This paper presents the results of a thermal coupon study investigating the effects of low temperature heat treatment on the tensile and compressive stress strain curves of samples taken from X100 linepipe. Thirty axial test coupons and thirty circumferential test coupons were machined from a 52 inch diameter, 21 mm wall thickness UOE X100 linepipe. Some of the coupons were maintained in the as-received condition (no heat treatment) while others were heat-treated in a manner that simulates a coating plant induction heat treatment process. All coupons were subsequently tested in tension or compression, either at room temperature or at −18°C. This study has provided a number of interesting results. In regards to material strength, the heat treatment increased the tensile and compressive yield strengths in the longitudinal and circumferential coupons. Axial tensile, axial compressive and circumferential tensile yield strength increases ranged from 5 to 10%. Circumferential compressive yield strength increases ranged from 14 to 24%. A Y/T ratio increase of approximately 7% was observed for all heat-treated tensile coupons. The coupon tests conducted at −18°C were only slightly different than their room temperature counterparts; with an average yield strength increase of 4% in all directions and orientations and a slight reduction in Y/T ratio.

Tailoring the Mechanical Properties of Al-Sn-Alloys for Tribological Applications

2007 ◽  
Vol 539-543 ◽  
pp. 317-322 ◽  
Author(s):  
Rafael Schouwenaars ◽  
J.A. Torres ◽  
Víctor H. Jacobo ◽  
Armando Ortiz
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Surface Tension ◽  
Low Temperatures ◽  
Phase Distribution ◽  
Cu Alloy ◽  
Heat Treated ◽  
Cold Rolled ◽  
Physical Phenomena

A 95% cold-rolled Al-20%Sn-1%Cu alloy was heat-treated in a range of temperatures and times to investigate the evolution of mechanical properties and microstructure. The most interesting combination of properties can be achieved between 300 and 400°C in a process that is simpler than what is used in industry. The physical phenomena which are active during the heat treatment are precipitation, recovery, recrystallisation and change in phase distribution due to surface tension. The former two predominate at low temperatures, while the latter achieve faster kinetics at higher temperatures, where recrystallisation is coupled to the change in morphology of the contiguous Sn-phase.

scholarly journals Characterization of Tensile Properties and Fracture Toughness of Equal Channel Angular Pressed Al-Zn Alloy

2021 ◽  
Author(s):  
Mohan kumar S ◽  
H K Govindaraju ◽  
M D Kiran
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Treatment Temperature ◽  
Artificial Ageing ◽  
Angular Pressing ◽  
Dislocation Strengthening ◽  
Zn Alloy

Abstract Influence of Equal channel angular pressing on mechanical properties and Fracture toughness of Al-Zn alloy were studied in present investigation. Samples are successfully processed using the ECAP technique for up to a four passes by using route A. Al-Zn alloys were heated to a solid solution treatment temperature at 550oC for 2 hours prior to ECAP, this treatment introduces the precipitates which were capable of obstructing motions of dislocation and improves the refinement of the grain during ECAP process Finally, artificial ageing was performed at a temperature of 190°C for 0-20 hours with an interval of 2 hr and specimens are cooledat room temperature with natural air.Fracture toughness was found experimentally for ECAP processed samples using SE (B) specimens according to ASTM E399 standard.Study revealed the enhancement in mechanical properties such as yield strength, ultimate strength and microhardness after four passes by route A technique.The improvement in the fracture toughness properties of artificially aged ECAP samples can also be due to dislocation strengthening, grain boundary strengthening, and the creation of much finer UFG grains, according to the results. Despite the increased tensile strength after ECAP, the ductility behaviour has decreased due to the precipitation of GP zones and dispersion of η, ή, T and E within the Aluminium matrix Furthermore, scanning electron microscope (SEM) micrographs revealed that ductile fracture with large dimples occurred in the artificial aged samples after the ECAP procedure.

REPUBLIC HP 9-4-45

Alloy Digest ◽  
1965 ◽  
Vol 14 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Yield Strength ◽  
Heat Treating ◽  
Isothermal Heat Treatment ◽  
Temperature Performance ◽  
Heat Treated ◽  
Thin Walled

Abstract Republic HP 9-4-45 is a heat treated alloy steel capable of developing a yield strength of 250,000 psi with superior toughness characteristics. It is designed for sheet and thin-walled forged sections. It is also designed for heavy forging where an isothermal heat treatment is employed. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-179. Producer or source: Republic Steel Corporation, Titanium Division.

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