scholarly journals Combining Equal-Channel Angular Extrusion (ECAE) and Heat Treatment for Achieving High Strength and Moderate Ductility in an Al-Cu Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 685-690 ◽  
Author(s):  
Matthias Hockauf ◽  
Lothar W. Meyer ◽  
Lutz Krüger
Keyword(s):  
Heat Treatment ◽  
Equal Channel Angular Extrusion ◽  
Failure Strain ◽  
Solution Treatment ◽  
High Strength ◽  
Ultimate Tensile Stress ◽  
Processing Temperature ◽  
Strength Increase ◽  
High Temperature Short Time ◽  
Angular Extrusion

The effect of equal-channel angular extrusion (ECAE) on mechanical properties of an AA2017 produced by powder metallurgy is investigated. Special attention is given to the influence of heat treatment, processing temperature and backpressure on the workability for achieving high strength and moderate ductility. This is of special interest, since it is often reported that Al-Cu alloys have low ductility and therefore are prone to cracking during severe plastic deformation. It is shown that ECAE at high temperatures (>220°C) does not necessitate backpressure to ensure homogeneous deformation but leads to a significant sacrifice in strength due to in-situ precipitation. Thus, most of the extrusions are done at considerably low temperatures. Performing room temperature-extrusion is most effective in achieving high strengths but also requires high backpressures. Due to severe strain hardening during processing, the strength increase is combined with a reduction in ductility. Recently it was reported that a post-ECAE aging of pre-ECAE solution treated material is effective in enhancing the ductility of aluminium alloys. This approach was successfully transferred to the current alloy. A high-temperature, short-time aging after only one extrusion, for example, doubles the failure strain to a value of ~13%. Compared to the naturally aged condition with coarse grains that serves as reference (T4), an increase of 15 % in yield stress (YS) was obtained while retaining the ultimate tensile stress (UTS). Another effective approach is the combination of a pre-ECAE solution treatment with subsequent under-aging prior to ECAE. It is shown that performing ECAE at medium temperatures (160-180°C) enables a better workability and additionally gives higher strengths and better ductility compared to the processing in the water quenched condition. A remarkable YS of 530 MPa and an UTS of 580 MPa combined with a moderate failure strain of 11.6 % were achieved.

The Effect of Heat Treatment on Formability of Ultra-Fine Grained AA6061 for Bolt Manufacturing

2010 ◽  
Vol 443 ◽  
pp. 164-169 ◽  
Author(s):  
Jun Seok Choi ◽  
Young Gwan Jin ◽  
Yong Taek Im
Keyword(s):  
Heat Treatment ◽  
Artificial Aging ◽  
Equal Channel Angular Extrusion ◽  
High Strength ◽  
Strength Increase ◽  
Fine Grained ◽  
Heat Treated ◽  
Before And After ◽  
Fine Grained Material ◽  
Set Up

Equal channel angular extrusion (ECAE) was used before and after artificial aging to investigate the effect of heat treatment on formability of bulk nanostructure of commercially available aluminum alloy of AA6061 in the present study. In the ECAE, route A was applied up to four or eight passes by using the split dies set-up. The three-stage bolt forming using the ultra-fine grained specimens was carried out to check formability of the material. In the present experiments, the bolt forming was successful with the specimen prepared by the ECAE after artificial aging whilst it was not successful with the specimen prepared by a reverse process sequence. The strength increase was confirmed by the tension and microhardness tests and compared to the result of conventional AA2024 bolt made by the conventionally heat treated specimen. It was found that the strength was comparable to the level of the heat treated conventional one although the actual value was a little bit lower. In addition, it was demonstrated that the heat treatment sequence is important to achieve proper formability of the ultra-fine grained material to manufacture the high strength bolt.

Mechanical Behaviour of Beta Titanium Alloys

2021 ◽  
Vol 1016 ◽  
pp. 964-970
Author(s):  
Nageswara Rao ◽  
Geetha Manivasagam
Keyword(s):  
Heat Treatment ◽  
Titanium Alloys ◽  
Dynamic Properties ◽  
Solution Treatment ◽  
Weight Ratio ◽  
High Strength ◽  
Static Properties ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Beta Titanium Alloys

Beta titanium alloys have several attractive features; this has resulted in this group of alloys receiving much attention since 1980’s. Among the attributes which distinguish them for their superiority over other structural materials are (i) high strength to which they can be heat treated, resulting in high strength to weight ratio (ii) high degree of hardenability which enables heat treatment in large section sizes to high strength levels (iii) excellent hot and cold workability, making them as competitive sheet materials etc. The standard heat treatment consists of solution treatment in beta or alpha plus beta phase field followed by aging. However, certain aging treatments can render the materials in a state of little or no ductility; the designer has to be aware of this behaviour and has to keep away from such treatments while working with the materials. Such unfavourable aging treatments may adversely affect not only the static properties such as reduction in area and elongation in a tensile test, but also dynamic properties such as impact toughness. Results of fractographic studies are in line with those of mechanical testing. The authors would present the foregoing analysis, based primarily on the wide-ranging researches they carried out on beta titanium alloy Ti15-3 and to some extent data published by researchers on other grades of beta titanium alloys. An attempt is made to explain the mechanisms underlying the embrittlement reactions that take place in beta titanium alloys under non-optimal aging treatments.

Improvement of Strength and Ductility by Combining Static Recrystallization and Unique Heat Treatment in Co-20Cr-15W-10Ni Alloy for Stent Application

2021 ◽  
Vol 1016 ◽  
pp. 1503-1509
Author(s):  
Kosuke Ueki ◽  
Soh Yanagihara ◽  
Kyosuke Ueda ◽  
Masaaki Nakai ◽  
Takayoshi Nakano ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Static Recrystallization ◽  
High Strength ◽  
Small Variation ◽  
Grain Structure ◽  
Fine Grain ◽  
High Temperature Short Time ◽  
Average Grain Size ◽  
Strength And Ductility

The Co-20Cr-15W-10Ni (CCWN, mass%) alloy has excellent corrosion resistance and strength-ductility balance and is applied in almost all balloon-expandable stent platforms. To further reduce the invasiveness of stent placement, it is necessary to reduce the diameter of the stent. That is, both high strength and high ductility should be achieved while maintaining a low yield stress. In our previous studies, it was discovered that low-temperature heat-treatment (LTHT) at 873 K improves the elongation of the CCWN alloy. In this study, we focused on the grain refinement by swaging and static recrystallization to improve the strength of the alloy. The as-swaged alloy was recrystallized at 1373–1473 K for 100–300 s, followed by LTHT. A fine grain structure with an average grain size of 3–17 μm was obtained by static recrystallization. The η-phase (M12X-M6X type precipitates, M: metallic elements, X: C and/or N) formed during the recrystallization at 1373–1448 K. The alloys recrystallized at 1448 and 1473 K had a homogeneous structure with a small variation in the grain size. On the other hand, the alloys recrystallized at 1373 and 1423 K had an inhomogeneous structure in which fine and coarse grains were mixed. Both the strength and ductility of the CCWN alloy were improved by combining high-temperature short-time recrystallization and LTHT.

scholarly journals Microstructure Evolution and Mechanical Properties of AZ80 Mg Alloy during Annular Channel Angular Extrusion Process and Heat Treatment

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4223 ◽  
Author(s):  
Xi Zhao ◽  
Shuchang Li ◽  
Fafa Yan ◽  
Zhimin Zhang ◽  
Yaojin Wu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Microstructure Evolution ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Annular Channel ◽  
Mg Alloy ◽  
Strengthening Effect ◽  
Β Phase ◽  
Angular Extrusion

Microstructure evolution and mechanical properties of AZ80 Mg alloy during annular channel angular extrusion (350 °C) and heat treatment with varying parameters were investigated, respectively. The results showed that dynamic recrystallization of Mg grains was developed and the dendritic eutectic β-Mg17Al12 phases formed during the solidification were broken into small β-phase particles after hot extrusion. Moreover, a weak texture with two dominant peaks formed owing to the significant grain refinement and the enhanced activation of pyramidal <c + a> slip at relative high temperature. The tension tests showed that both the yield strength and ultimate tensile strength of the extruded alloy were dramatically improved owing to the joint strengthening effect of fine grain and β-phase particles as compared with the homogenized sample. The solution treatment achieved the good plasticity of the alloy resulting from the dissolution of β-phases and the development of more equiaxed grains, while the direct-aging process led to poor alloy elongation as a result of residual eutectic β-phases. After solution and aging treatment, simultaneous bonding strength and plasticity of the alloy were achieved, as a consequence of dissolution of coarse eutectic β-phases and heterogeneous precipitation of a large quantity of newly formed β-phases with both the morphologies of continuous and discontinuous precipitates.

scholarly journals Effect of T6 on Mechanical Properties of TiB and Sr Modified ADC12/SiC Composite Produced by Stir Casting

2019 ◽  
Vol 130 ◽  
pp. 01023
Author(s):  
Pritamara Wahyuningtyas ◽  
Anne Zulfia Syahrial ◽  
Wahyuaji Narottama Putra ◽  
Budi Wahyu Utomo
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Solution Treatment ◽  
Grain Morphology ◽  
High Strength ◽  
Stir Casting ◽  
Strength Properties ◽  
Grain Refiner ◽  
Brake Shoe ◽  
The Impact

A study of ADC12 (Al-Si aluminium alloy) composite is conducted to obtain a more sustainable material with enhanced properties for automotive industry purpose, such as train's brake shoe and bearing application. For those kind of utilization, material with durability, good elastic modulus, thermal stability, wear resistance, and high strength properties is needed due to its exposure to high temperature and heavy continuous application. ADC 12 acts as the matrix, reinforced with 3 vf% micro-SiC with 5 wt% Mg wetting agent was fabricated by the stir casting method. The addition of 0.18 wt% Sr and 0.15 wt% TiB were expected to finer the grain morphology of the silicone eutectic phase and to acts as the grain refiner, respectively. Furthermore, T6 heat treatment was applied with aging temperature 150 °C, 170 °C, 190 °C, 210 °C, and 230 °C, following the prior 1 h 490 °C solution treatment. The results obtained in this work showed enhancement in tensile strength with the value of 213 MPa, hardness value 75 HRB, and wear resistance. These values increase up to 115 MPa for the UTS and 38 HRB for the hardness value, as the impact of the refined grains from both modifiers and heat treatment.

Residual Stresses Resulting from the Forming of High Strength Aluminium Alloys

1959 ◽  
Vol 63 (578) ◽  
pp. 90-94
Author(s):  
G. A. Hawkes
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Residual Strain ◽  
Aluminium Alloys ◽  
Solution Treatment ◽  
High Strength ◽  
Hot Forming ◽  
X Ray ◽  
Back Reflection ◽  
Surface Residual Stresses

Summary:An X-ray back reflection technique has been used to measure the surface residual stresses resulting from the cold and hot forming of certain high strength aluminium alloys. The alloys examined were to specifications DTD 683, DTD 687 and B.S.S. L65, and the residual stresses have been related to the residual strain in bending of these alloys. The results show that, apart from the degree of straining, the residual stresses are affected by the heat treatment (cold or hot quench) and the amount (if any) of controlled stretching that the alloy has had between solution treatment and precipitation.

scholarly journals Semi-Continuous Equal-Channel Angular Extrusion and Rolling of AA5083 and AZ31 Alloys

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1035 ◽  
Author(s):  
Vladimir Segal ◽  
Svetlana V. Reznikov ◽  
Nagendra Murching ◽  
Vincent H. Hammond ◽  
Laszlo J. Kecskes
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Large Scale ◽  
Equal Channel Angular Extrusion ◽  
Solution Treatment ◽  
Structure And Properties ◽  
Structural Refinement ◽  
Angular Extrusion ◽  
Lightweight Alloys ◽  
Technical Basis

This paper describes a new modification of equal-channel angular extrusion for the “pass-by-pass” semi-continuous (sc-ECAE) processing of lightweight alloys. Sc-ECAE leads to a multifold increase in productivity and decrease in costs, providing a technical basis for the commercialization of severe plastic deformation (SPD) on a large scale with massive volume production. The evolution of the structure and properties are analyzed for an aluminum alloy (AA) 5083 and a magnesium alloy AZ31 as model materials representing, respectively, the structural refinement under severe plastic deformation (SPD) via strain-induced formation of new grain boundaries and via dynamic recrystallization. For the first alloy, the microstructure after sc-ECAE is formed via ultrafine sub-grains, which are further transformed into sub-micrometer grains during post-ECAE rolling. The preliminary solution treatment of AA5083 is an important stabilizing factor for the achievement of high mechanical properties. For the second alloy, optimized sc-ECAE results in a remarkable structural refinement, and a good balance of properties is obtained with a low number of passes. However, additional rolling in the latter case leads to a degradation of the structure and properties.

Study on Microstructures and Mechanical Properties of Die Casting Mg-xGd-3Y-0.5Zr Alloys

2013 ◽  
Vol 690-693 ◽  
pp. 44-48
Author(s):  
Feng Wang ◽  
Zhi Wang ◽  
Zheng Liu ◽  
Ping Li Mao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Solution Heat Treatment ◽  
Die Casting ◽  
Solution Treatment ◽  
Small Variation ◽  
Strength Increase ◽  
Microstructures And Mechanical Properties ◽  
Zr Alloys

In this paper, developed a non-aluminum die casting magnesium alloys were studied based on Mg-xGd-Y-Zr（x=6, 8, 12 wt.%）alloys in cold chamber press. The microstructures and mechanical properties of die casting GWK alloys have been investigated using OM, SEM, XRD, EDS and mechanical property test. The experimental results show that with increasing Gd content of Mg-xGd-Y-Zr alloys, the tensile strength increase, but elongation decrease. In particular, die casting GWK alloys after short-term and low-temperature solid solution treatment (T4) have a small variation in grain size and more uniform microstructures, and the second phases distribute at the grain boundaries in form of discontinuous rod shape or granule shape, which result in an obvious improvement in tensile mechanical properties of alloys. The Mg-12Gd-3Y-0.5Zr die casting alloy exhibit maximum tensile strength after solution heat treatment, and the value is 269MPa at room temperature. The effect of solution heat treatment on die casting Mg-xGd-Y-Zr alloys was also discussed.

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