scholarly journals Recovery of deformation substructure and coarsening of particles on annealing severely plastically deformed Al–Mg–Si alloy and analysis of strengthening mechanisms

2006 ◽  
Vol 21 (2) ◽  
pp. 329-342 ◽  
Author(s):  
I. Gutierrez-Urrutia ◽  
M.A. Muñoz-Morris ◽  
D.G. Morris
Keyword(s):  
Tensile Testing ◽  
Strengthening Mechanisms ◽  
Grain Coarsening ◽  
Angular Pressing ◽  
Dispersed Particles ◽  
Deformation Substructure ◽  
Heat Treated ◽  
Dislocation Strengthening ◽  
Treated State ◽  
Initial Heat

An Al–Mg–Si alloy was annealed to various solutionized and aged states and was then severely plastically deformed by equal channel angular pressing (ECAP). These materials were subsequently annealed for a range of times and temperatures to induce precipitation, dislocation recovery, and grain growth, with changes of mechanical behavior followed by tensile testing. Precipitation of excess solute was seen to occur in all cases, independent of the initial heat treated state, but the particles present appear to play only a small role in stabilizing the deformation substructure, at least until significant particle and grain coarsening has occurred, when discontinuous grain coarsening can be provoked. The strength of materials is examined, and the respective contributions of loosely arranged dislocations, many grain boundaries, and dispersed particles are deduced. It is shown that dislocation strengthening is significant in as-deformed, as well as lightly annealed materials, with grain boundary strengthening providing the major contribution thereafter.

The Effects of Hot Isostatic Pressing on Aluminium Castings

2007 ◽  
Vol 345-346 ◽  
pp. 1545-1548
Author(s):  
Markus Ostermeier ◽  
Hartmut Hoffmann ◽  
Ewald Werner
Keyword(s):  
Tensile Strength ◽  
Tensile Testing ◽  
Hot Isostatic Pressing ◽  
Casting Process ◽  
Initial State ◽  
Isostatic Pressing ◽  
Heat Treated ◽  
Initial Heat ◽  
Initial Heat Treatment

Since the early 1960s hot isostatic pressing (HIP) was used to improve the quality of castings made of various alloys. The closure of pores, originating from the casting process, is considered as the main source of these improvements. For the aluminium alloy Al-9Si-3Cu specimens for tensile testing were machined from castings either squeeze casted and heat treated to T4 and T6 conditions or investment casted. The effect of HIP on density, roughness and mechanical properties was investigated. The density and roughness of the squeeze casted specimens did not change remarkably and their tensile strength became worse, because the initial heat-treatment-state was destroyed by HIP. The investment casted specimens became denser and roughness became worse due to closure of pores near the surface. Although roughness after HIP was higher than in the initial state, tensile strength was improved significantly by HIP, because of closure of the pores in the specimen.

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

Improvement of Strength of Mg-12Gd-3Y-0.5Zr Alloys Processed by Combination of ECAP and Extrusion

2011 ◽  
Vol 682 ◽  
pp. 211-216
Author(s):  
Rong Zhu ◽  
Jin Qiang Liu ◽  
Jing Tao Wang ◽  
Ping Huang ◽  
Yan Jun Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Grain Boundary ◽  
Low Temperatures ◽  
Basal Slip ◽  
Extrusion Direction ◽  
Strengthening Mechanisms ◽  
Step Process ◽  
Angular Pressing ◽  
Peak Intensity

Equal channel angular pressing (ECAP) has been used to refine the grain size of Mg-12Gd-3Y-0.5Zr billet at about 400°C because it lacks sufficient ductility at low temperatures. However, <0001> peak intensity is oriented about 50º from the extrusion direction, which facilitates the basal slip, and decreases the yield strength. We have employed conventional extrusion at 300°C following ECAP to modify the texture in hard orientation. This two-step process makes use of two strengthening mechanisms a) grain boundary strengthening due to small grain size, and (b) texture strengthening due to grains in hard orientation. The samples processed by the two-step show the yield and ultimate strength to 283 and 308 MPa, respectively. Moreover, the activation of <c+a> slip and fine grains resulted from the ECAP helped to maintain a good ductility even after significant straining from conventional extrusion.

scholarly journals Multi-strengthening-mechanisms in a novel titanium alloy with (TiHf)5Si3 particle-reinforcement

2020 ◽  
Vol 321 ◽  
pp. 11078
Author(s):  
Yan Du ◽  
Jinwen Lu ◽  
Wei Zhang ◽  
Yusheng Zhang
Keyword(s):  
Dislocation Motion ◽  
Heat Treatments ◽  
Triple Junctions ◽  
Strengthening Mechanisms ◽  
Particle Reinforcement ◽  
Solid Solution Strengthening ◽  
Long Period ◽  
Solution Strengthening ◽  
Dislocation Strengthening ◽  
Particle Strengthening

The microstructure and mechanical properties of Ti-2Si-2Nb-2Fe-1Hf-1Ta-1W alloy with (TiHf)5Si3 particle-reinforcement and their underlying relations have been studied. Electron microscope observations and correlative statistical analysis have been made to analyze microstructure evolution with heat treatments. The (TiHf)5Si3 particles with 800 nm in diameter were found uniformly distributed at α/β boundaries and triple junctions and turned out to be stable even after heat treatments at high temperature for a long period, inhibiting grain growth and dislocation motion. In addition, multi-strengthening-mechanisms including particle strengthening, solid-solution strengthening, grain boundary strengthening and dislocation strengthening have been discussed.

Characterization of Microstructure and Mechanical Properties of 6060 Aluminum Alloy Processed by ECAP

2018 ◽  
Vol 275 ◽  
pp. 81-88
Author(s):  
Monika Karoń ◽  
Marcin Adamiak
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Internal Stresses ◽  
Refined Grains ◽  
Angular Pressing ◽  
Heat Treated ◽  
Evolution Of Microstructure

The purpose of this paper is to present the microstructure and mechanical behavior of 6060 aluminum alloy after intense plastic deformation. Equal Channel Angular Pressing (ECAP) was used as a method of severe plastic deformation. Before ECAP part of the samples were heat treated to remove internal stresses in the commercially available aluminium alloy. The evolution of microstructure and tensile strength were tested after 1, 3, 6 and 9 ECAP passes in annealed and non annealed states. It was found that intensely plastically deformed refined grains were present in the tested samples and exhibited increased mechanical properties. Differences were noted between samples without and after heat treatment

Evaluation of 4330M Steel for Fasteners Applications

2017 ◽  
Vol 380 ◽  
pp. 198-211 ◽  
Author(s):  
A. Al Sumait ◽  
C. Delgado ◽  
F. Aldhabib ◽  
X. Sun ◽  
F. Alzubi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Testing ◽  
Grain Structure ◽  
Hardness Testing ◽  
Heat Treated ◽  
Different Types ◽  
Strength And Ductility ◽  
Scanning Electron

The objective of the study was to optimize the strength and ductility values of the 4330M steel. Optimization was conducted through different types of heat treatments. Tensile testing, hardness testing, optical microscopy, and Scanning Electron Microscopy (SEM) were used to evaluate the mechanical properties and microstructure of the as-received and the heat treated samples. The alloy was provided from two vendors; vendor H and vendor S. Results showed that by increasing the tempering temperatures, strength values decreases, while ductility values remain unchanged. Vendor H samples had higher strength values and much finer grain structure which was revealed only at 5000x magnification.

Precipitation Studies of Undeformed and ECAP-Deformed Al-4%Cu Alloys: Effects on Microstructure and Tensile Properties

2008 ◽  
Vol 584-586 ◽  
pp. 708-715 ◽  
Author(s):  
Erika Fernanda Prados ◽  
Vitor Luiz Sordi ◽  
Maurizio Ferrante
Keyword(s):  
Initial Conditions ◽  
Tensile Tests ◽  
Solution Temperature ◽  
Tensile Behaviour ◽  
Total Strength ◽  
Angular Pressing ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Heat Treated ◽  
Precipitation Heat

The present study is an assessment of the effects of precipitation heat treatments on tensile behaviour, work hardening (WH) characteristics and microstructural evolution of an Al-4%Cu alloy deformed by equal channel angular pressing (ECAP). Two ageing temperatures were employed (170 and 100oC) and their effect on strength and WH behaviour was compared with that exerted on the same alloy, but in two different initial conditions: quenched from solution temperature and slowly cooled before anneal. Grain and precipitate sizes of samples deformed by one and four ECAP passes and heat treated as described were measured employing transmission electron microscopy (TEM). It was concluded that the lower ageing temperature gives the best combination of strength and ductility, a high WH rate and, possibly, the smaller grain and precipitate sizes. The relative participation of the various hardening mechanisms to total strength was estimated from tensile tests and hardness measurements.

An Investigation of Hardness and Microstructure Evolution of Heat Treatable Aluminum Alloys during and after Equal-Channel Angular Pressing

2009 ◽  
Vol 633-634 ◽  
pp. 333-340
Author(s):  
Emanuela Cerri
Keyword(s):  
Aging Temperature ◽  
Precipitation Hardening ◽  
Aging Effect ◽  
X Rays ◽  
Microstructure Modification ◽  
Angular Pressing ◽  
Heat Treated ◽  
Polarised Light ◽  
Lower Aging Temperature ◽  
Deformed State

The influence of severe plastic deformation induced by ECAP on microstructure modification and aging effect was studied in two modified Al-Mg-Si aluminium alloys. The microstructure of both alloys in different heat treated and deformed state was characterised by X-Rays diffraction and polarised light microscopy. The effect of artificial aging was investigated after ECAP performed on samples in the as extruded condition. The aging effect was followed by hardness and electrical conductivity measurements. At higher aging temperature (170°C) the alloys showed an increasing softening with time due to recovery or/and grain coarsening effect. At the lower aging temperature, the hardness remains almost constant due to enhanced precipitation hardening effect.

An Investigation of Cavitation in the Tensile Testing of a Spray-Cast Aluminum Alloy Processed by ECAP

2006 ◽  
Vol 503-504 ◽  
pp. 83-90 ◽  
Author(s):  
Megumi Kawasaki ◽  
Cheng Xu ◽  
Terence G. Langdon
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Strain Rate ◽  
Tensile Testing ◽  
Ultrafine Grain ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Angular Pressing ◽  
Cavity Development ◽  
Spray Casting

A commercial aluminum 7034 alloy, produced by spray casting and having an initial grain size of ~2.1 μm, was subjected to equal-channel angular pressing (ECAP) through six passes at 473 K. In the as-pressed condition, the microstructure was reasonably homogeneous and the grain size was reduced to an ultrafine grain size of ~0.3 μm. This alloy contains MgZn2 and Al3Zr precipitates which restrict grain growth. In tensile testing at 673 K after processing by ECAP, an elongation of >1000% was achieved at a strain rate of 1.0 × 10-2 s-1 corresponding to high strain rate superplasticity. Quantitative cavity measurements were conducted on the specimens after tensile testing for both the as-received condition and after ECAP. These measurements reveal a significant number of small cavities in the samples and especially in the sample that exhibited a very high elongation. This paper describes the morphology of cavity development in the spray-cast aluminum alloy in both the as-received and as-pressed condition.

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