scholarly journals Probability-Dependent Precipitation Strengthening Effect of Anisotropic Precipitate in Al-Mg-Si Alloy Produced by T6 Heat Treatment

2021 ◽  
Vol 59 (8) ◽  
pp. 515-523
Author(s):  
Seunggyu Choi ◽  
Gwanghun Kim ◽  
Jin Pyeong Kim ◽  
Se Hoon Kim ◽  
Seung Bae Son ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Metastable Phase ◽  
Precipitation Strengthening ◽  
Precipitate Size ◽  
Strengthening Effect ◽  
Alloy Matrix ◽  
Gravity Casting ◽  
T6 Heat Treatment ◽  
Critical Resolved Shear Stress

This study proposed a constitutive equation to predict the change in yield strength according to the behavior of β″ metastable precipitates, which have a profound effect on strength among materials precipitated during the T6 heat treatment of Al-Mg-Si alloy. The β″ precipitate is a metastable phase before it becomes a β (Mg2Si) precipitate, and is distributed in the form of nano-scale rods in the aluminum alloy matrix. Existing precipitation strengthening models assume the shape of the precipitate to be spherical, and in that case the equation that depends on the Orowan mechanism with the average precipitate size and distribution should dominate. However, precipitates are formed in various shapes and sizes by anisotropic growth. In particular, rod-shaped precipitates are not suitable for the existing precipitation strengthening model. In this study, an Al-Mg-Si alloy was fabricated by gravity casting followed by T6 heat treatment. The new precipitation strengthening effect equation proposes that the β″ precipitate affects yield strength during plastic deformation of the Al-Mg-Si alloy. The proposed precipitation strengthening effect equation probabilistically considers the Critical Resolved Shear Stress (CRSS), which varies depending on the angle between the dislocation and the precipitate, when the dislocation passes through a rod-shaped precipitate.

Microstructure and Mechanical Properties of TiB2/ Al-Si Composites Fabricated by TIG Wire and Arc Additive Manufacturing

2019 ◽  
Vol 944 ◽  
pp. 64-72
Author(s):  
Qing Feng Yang ◽  
Cun Juan Xia ◽  
Ya Qi Deng
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Yield Strength ◽  
Filler Wire ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Before And After

Bulky sample was made by using TIG wire and arc additive manufacturing (WAAM) technology, in which Ф1.6 mm filler wire of in-situ TiB2/Al-Si composites was selected as deposition metal, following by T6 heat treatment. The microstructure and mechanical properties of the bulky sample before and after heat treatment were analyzed. Experimental results showed that the texture of the original samples parallel to the weld direction and perpendicular to the weld direction was similar consisting of columnar dendrites and equiaxed crystals. After T6 heat treatment, the hardness of the sample was increased to 115.85 HV from 62.83 HV, the yield strength of the sample was 273.33 MPa, the average tensile strength was 347.33 MPa, and the average elongation after fracture was 7.96%. Although pore defects existed in the fracture, yet the fracture of the sample was ductile fracture.

scholarly journals The Microstructure Evolution and Mechanical Properties of TiBw/TA15 Composite with Network Structure Prepared by Rapid Current Assisted Sintering

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 540 ◽  
Author(s):  
Dongjun Wang ◽  
Hao Li ◽  
Xiaosong Wang ◽  
Wei Zheng ◽  
Zhangqian Lin ◽  
...  
Keyword(s):  
Yield Strength ◽  
Microstructure Evolution ◽  
Average Diameter ◽  
Strengthening Mechanism ◽  
Strengthening Effect ◽  
Alloy Matrix ◽  
Microstructure Modification ◽  
Ta15 Titanium Alloy ◽  
Average Aspect Ratio ◽  
Rapid Current

TiBw/TA15 (TA15 alloy reinforced by TiB whiskers) composites with network microstructures were successfully prepared by current-assisted sintering at 1100 °C for 10 min. The influence of the sintering parameters on the microstructures of obtained composites was investigated. The sintering temperature was the main factor affecting the average aspect ratio of TiBw, and the average diameter of TiBw could be controlled for various sintering conditions. Yield strength, ultimate compressive strength, and plastic strain at ambient temperature are 1172.5 MPa, 1818.4 MPa, and 22.4% for the TiBw/TA15 composites, respectively. Moreover, yield strength of the composites at 600 °C is 616.3 MPa, which is 26.1% higher than that of the TA15 titanium alloy. The effect of the TiBw on the microstructure evolution for the alloy matrix was discussed in detail. The strengthening mechanism of the TiBw/TA15 composites with network microstructure was attributed to the microstructure modification induced by TiBw, load bearing effect, and dislocation strengthening effect of the TiBw.

Comparison Study of As-Cast and T6 Condition of Microstructure, Bending Strength and Double Shear Strength of A356 Alloy by Gravity, Vacuum and Squeeze Casting

2014 ◽  
Vol 592-594 ◽  
pp. 102-105 ◽  
Author(s):  
K. Sekar ◽  
Allesu Kanjirathikal ◽  
M.A. Joseph
Keyword(s):  
Heat Treatment ◽  
Shear Strength ◽  
Squeeze Casting ◽  
Bending Strength ◽  
A356 Alloy ◽  
Gravity Casting ◽  
Vacuum Casting ◽  
T6 Heat Treatment ◽  
Double Shear ◽  
Treatment Conditions

The hardness, bending strength, and double shear strength of A356 aluminium alloy was studied under as cast and T6 heat treatment conditions obtained with gravity casting, vacuum casting and squeeze casting methods. The results of these three casting methods have been compared. The hardness, bending strength of A356 alloy after T6 obviously increased; the hardness value of both vacuum casting and squeeze casting has been found to be 62 HRB which is relatively high compared to gravity casting. The bending strength of gravity casting is 299 MPa (22% increase) compared to vacuum casting. However, after T6 heat treatment, the double shear strength values of all these three castings decreases.

scholarly journals Quantification and Modelling of the Multiphase-Coupled Strengthening Effect in Al-Cu-Li Alloy

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1038
Author(s):  
Jin Zhang ◽  
Zhide Li ◽  
Fushun Xu ◽  
Chongjun Bao
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Precipitation Strengthening ◽  
Strengthening Effect ◽  
Superposition Model ◽  
Aging Heat Treatment ◽  
Volume Fractions ◽  
Age Strengthening ◽  
Precipitated Phases ◽  
Strengthening Phases

After aging heat treatment, Al-Cu-Li alloy, in general, contains a variety of precipitated phases that jointly influence the age-strengthening effect on the alloy. In this work, a multiphase-coupled strengthening model has been established on the basis of a dislocation bypassing mechanism. The model considered situations with different proportions of two strengthening phases, T1 and θ′, and then obtained the dimension and volume fractions of these two strengthening phases via experiments. The values predicted by the multiphase-coupled strengthening model and the classical strengthening superposition model were compared with the measured results. The multiphase-coupled strengthening model established in this work had better consistency with the measured results. Moreover, the modeling method proposed in the paper can also be extended to the system having over two primary strengthening phases. Hence, the model can contribute towards the development of a multi-component precipitation strengthening process for aluminum alloys.

The Effects of T5 and T6 Heat Treatments on Wear Behaviour of AA6063 Alloy

2014 ◽  
Vol 33 (3) ◽  
pp. 231-237 ◽  
Author(s):  
Dursun Özyürek ◽  
Tansel Tunçay ◽  
Hasan Kaya
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Wear Test ◽  
Wear Behaviour ◽  
Precipitate Size ◽  
T6 Heat Treatment ◽  
Heat Treated ◽  
Pin On Disc ◽  
Aa6063 Alloy ◽  
Equipment Wear

AbstractIn this study, T5 heat treatment was applied to AA6063 alloy aged at 455 K for 2 hours after extrusion at 686 K. T6 heat treatment was also carried out by ageing at 455 K for 2 hours after solution heat treatment at 794 K for 1 hour. Heat treated T5 and T6 specimens were tested by pin-on-disc type wear equipment. Wear test was carried out by using 10, 20, 30 N loads and 400, 800, 1200 and 1600 m wear distance. T5 and T6 heat treated specimens were characterized with scanning electron microscope, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and hardness measurements. Worn surfaces of the specimens was also characterised with SEM. The results indicated that small and homogenously dispersed Mg2Si precipitates formed in AA6063 aluminium alloy with T6 heat treatment were compared to the T5 heat treatment. As a result of increment precipitate size, wear resistance decreased. T6 heat treated specimens showed higher hardness compared to the T5 heat treated specimens. In addition wear resistance and friction coefficient of both T5 and T6 heat treated specimens decreased with increasing applied load.

Study of the porosity produced in an aluminum alloy matrix composite due to a T6 heat treatment

2004 ◽  
Vol 35 (8) ◽  
pp. 2503-2510 ◽  
Author(s):  
A. García-Romero ◽  
A. M. Irisarri ◽  
M. Anglada ◽  
C. García-Cordovilla
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Matrix Composite ◽  
Alloy Matrix ◽  
T6 Heat Treatment ◽  
Aluminum Alloy Matrix

Nano-Scaled Fe3C Precipitates and Precipitation Strengthening in Hot Rolled Low Carbon High Strength Titanium Microalloyed Steel

2010 ◽  
Vol 146-147 ◽  
pp. 838-843
Author(s):  
Jian Feng Wang ◽  
Guang Qiang Li ◽  
Ai Da Xiao ◽  
Fu Jie
Keyword(s):  
Yield Strength ◽  
Microalloyed Steel ◽  
High Strength ◽  
Granular Bainite ◽  
Precipitation Strengthening ◽  
Strengthening Effect ◽  
Low Carbon ◽  
High Resolution Tem ◽  
Bainite Microstructure ◽  
Hot Rolled

Hot rolled Ti microalloyed steel with polygonal ferrite and granular bainite microstructure and 640 MPa yield strength has been developed in BOF-CSP process. By chemical phase analysis, XRD, EDS and high resolution TEM, the particle size distribution, morphology, composition, crystal structure of precipitates were identified. Results revealed the steel containing Ti exhibits fine and uniformly distributed Fe3C-type carbides, the amount of M3C particles less than 18 nm in size was 0.2565 mass %. The high strength of steel is attributed to the precipitation strengthening effect of Fe3C, the yield strength increment from precipitation strengthening of Fe3C calculated according to the formula by Olson and Ashby-Orowan attained 234.4 MPa.

Viability of turbine blade material with a long service life

2019 ◽  
pp. 28-35
Author(s):  
O. B. Berdnik ◽  
I. N. Tsareva ◽  
M. K. Chegurov
Keyword(s):  
Heat Treatment ◽  
Service Life ◽  
Yield Strength ◽  
Mechanical Characteristics ◽  
Operating Time ◽  
Structural Features ◽  
Operating Conditions ◽  
Standard Methods ◽  
Experimental Values ◽  
Plasticity Coefficient

This article deals with structural features and characteristic changes that affect the mechanical characteristics after different service life in real conditions using the example of the blades of the 4th stage of turbine GTE-45-3 with an operating time of 13,000 to 100,000 hours. To study the change in the state of the material under different operating conditions, determine the degree of influence of heat treatment on the regeneration of the microstructure, and restore the mechanical characteristics of the alloy after different periods of operation, non-standard methods were used: relaxation tests on miniature samples to determine the physical yield strength and microplasticity limit and quantitative evaluation of the plasticity coefficient of the material from experimental values of hardness, which allow us to identify the changes occurring in the microvolumes of the material and predict the performance of the product as a whole.

scholarly journals ODS EUROFER Steel Strengthened by Y-(Ce, Hf, La, Sc, and Zr) Complex Oxides

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1148 ◽  
Author(s):  
Roman Husák ◽  
Hynek Hadraba ◽  
Zdeněk Chlup ◽  
Milan Heczko ◽  
Tomáš Kruml ◽  
...  
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Complex Oxides ◽  
Oxide Dispersion Strengthened ◽  
Interparticle Spacing ◽  
Oxide Dispersion ◽  
Strengthening Effect ◽  
Dispersion Strengthening ◽  
Doping Element ◽  
Average Grain Size

Oxide dispersion-strengthened (ODS) materials contain homogeneous dispersions of temperature-stable nano-oxides serving as obstacles for dislocations and further pinning of grain boundaries. The strategy for dispersion strengthening based on complex oxides (Y-Hf, -Zr, -Ce, -La) was developed in order to refine oxide dispersion to enhance the dispersion strengthening effect. In this work, the strengthening of EUROFER steel by complex oxides based on Y and elements of the IIIB group (lanthanum, scandium) and IVB group (cerium, hafnium, zirconium) was explored. Interparticle spacing as a dispersoid characteristic appeared to be an important factor in controlling the dispersion strengthening contribution to the yield strength of ODS EUROFER steels. The dispersoid size and average grain size of ODS EUROFER steel were altered in the ranges of 5–13 nm and 0.6–1.7 µm, respectively. Using this strategy, the yield strength of the prepared alloys varied between 550 MPa and 950 MPa depending on the doping element.

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