Enhanced mechanical properties in ultrafine grained 7075 Al alloy

2005 ◽  
Vol 20 (2) ◽  
pp. 288-291 ◽  
Author(s):  
Y.H. Zhao ◽  
X.Z. Liao ◽  
Y.T. Zhu ◽  
R.Z. Valiev

Highest strength for 7075 Al alloy was obtained by combining the equal-channel-angular pressing (ECAP) and natural aging processes. The tensile yield strength and ultimate strength of the ECAP processed and naturally aged sample were 103% and 35% higher, respectively, than those of the coarse-grained 7075 Al alloy counterpart. The enhanced strength resulted from high densities of Guinier–Preston (G-P) zones and dislocations. This study shows that severe plastic deformation has the potential to significantly enhance the mechanical properties of precipitate hardening 7000 series Al alloys.

2004 ◽  
Vol 821 ◽  
Author(s):  
Yonghao Zhao ◽  
Xiaozhou Liao ◽  
Ruslan Z. Valiev ◽  
Yuntian T. Zhu

AbstractEqual-channel angular pressing (ECAP) processed ultrafine grained (UFG) and coarse grained (CG) 7075 Al alloys were treated by natural aging and T651 temper (annealed at 120 °C for 48 h in Ar atmosphere), respectively. Mechanical tests showed that for the UFG sample, the natural aging resulted in the highest strength (the ultimate tensile strength is 720 MPa). In contrast, for the CG sample, the T651 treatment resulted in a higher strength (the ultimate strength is 590 MPa) than the natural aging (530 MPa). Microstructural analyses indicated that the enhanced strength of the T651 treated CG sample was mainly caused by high densities of G- P zones and metastable η' precipitates. The enhanced strength of the naturally aged UFG sample was mainly caused by the high densities of G-P zones and dislocations. Upon T651 treatment, the dislocation density of the UFG sample deceased significantly, overcompensating the precipitation strengthening.


2008 ◽  
Vol 584-586 ◽  
pp. 501-506 ◽  
Author(s):  
Nguyen Q. Chinh ◽  
Jenő Gubicza ◽  
Tomasz Czeppe ◽  
Janos Lendvai ◽  
Zoltán Hegedűs ◽  
...  

This work is focused on the effect of the combination of natural aging and severe plastic deformation (SPD) produced by Equal-Channel Angular Pressing (ECAP) on the microstructure and strength of supersaturated AlZnMg alloys. Following a solution heat-treatment and quenching into water at room temperature, samples were naturally aged for different time periods and then processed by ECAP. The microstructure and mechanical properties of these samples are described and discussed. This investigation leads to proposing an interesting application of ECAP for supersaturated alloys. Using the shear bands created by ECAP in only one pass and applying appropriate subsequent aging treatments, composite-like microstructures can be achieved in conventional age-hardenanble Al alloys.


2016 ◽  
Vol 879 ◽  
pp. 1317-1322 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Yuzbekova ◽  
Tatiana Lebedkina ◽  
Mikhail Lebyodkin ◽  
Rustam Kaibyshev

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.


2008 ◽  
Vol 584-586 ◽  
pp. 315-326 ◽  
Author(s):  
Shao Hua Xia ◽  
L.V. Vychigzhanina ◽  
Jing Tao Wang ◽  
Igor V. Alexandrov

In the present investigation, a bimodal structured alloy with ultrafine-grained (UFG) eutectoid matrix embedded with micrometer-grained pre-eutectoid phase was introduced into the hypo-eutectoid Cu-10.8wt.%Al and Cu-11.3wt.%Al alloys by means of pre-pressing heat-treatment, equal-channel-angular pressing (ECAP) and subsequent annealing. Different size of micrometer grained pre-eutectoid phase was obtained by controlling the cooling rate during pre-pressing heat-treatment of the hypo-eutectoid alloy. The tensile deformation behavior of the developed microstructures is characterized by a maximum tensile yield strength up to 800MPa, which is three times higher than that of the un-treated alloy. It is found that the size of the micrometer grained pre-eutectoid phase is critical to the improvement of the bimodal structured alloy. With larger micrometer grained pre-eutectoid phase, no obvious improvement in plastic elongation was observed with the increase of volume fraction of the pre-eutectoid phase from 20% to 40%, but a decrease in the yield tensile strength was observed. An optimal combination of strength and ductility was obtained particularly in those samples embedded with small-sized micrometer-grained pre-eutectoid phase, which provide extra strain gradient hardening effect.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7739
Author(s):  
Gennadiy V. Klevtsov ◽  
Ruslan Z. Valiev ◽  
Natal’ya A. Klevtsova ◽  
Maxim N. Tyurkov ◽  
Mikhail L. Linderov ◽  
...  

In this paper, we study the corrosion-resistant austenitic steel Fe-0.02C-18Cr-8Ni for medical applications. The microstructure and mechanical properties (tensile mechanical properties, torsional strength, impact toughness, and static and cyclic crack resistance) under different types of loading of the steel are investigated. The results are compared for the two states of the steel: the initial (coarse-grained) state and the ultrafine-grained state produced by severe plastic deformation processing via equal-channel angular pressing. It is demonstrated that the ultrafine-grained steel 0.08C-18Cr-9Ni has essentially better properties and is very promising for the manufacture of medical products for various applications that experience various static and cyclic loads during operation.


2012 ◽  
Vol 629 ◽  
pp. 198-202 ◽  
Author(s):  
Ping Yang ◽  
Kai Huai Yang

Three groups of commercial 1050 Al alloy were subjected to equal channel angular pressing (ECAP) at room temperature using route A, route C and route Bc, respectively. Mechanical properties and fracture modes of as-annealed and ECAPed samples were investigated. The microhardness of 1050 Al fabricated by ECAP increases by a factor of about 1.5 compared to the as-annealed state. The ultimate tensile strength (UTS) increases significantly after ECAP, while the elongation decreases. But they are strongly dependence on the number of ECAP passes and the pressing route. The UTS and elongation of the samples processed by route Bc are best, consequently, the static toughness U of the samples is enhanced. Besides, all specimens subjected to ECAP deformation failed in a ductile manner.


2006 ◽  
Vol 503-504 ◽  
pp. 663-668 ◽  
Author(s):  
Jing Tao Wang ◽  
Zhong Ze Du ◽  
Feng Kang ◽  
Guang Chen

Pure copper (99.98%wt) square bars (32x32 mm) were processed by equal channel angular pressing (ECAP) Microstructure evolution was characterized by microscopy. Room temperature mechanical properties were obtained by tensile and micro-hardness tests. With increasing number of ECAP passes and cold rolling reductions, the initial coarse grained structure in the as-received material was transformed gradually into an ultrafine grained microstructure with an average grain size of 0.2~0.3 μm. Subsequent rolling resulted deformation twining in this ultrafine grained microstructure, which gives further strengthening in addition to the strengthening obtained by ECAP. Property anisotropy in three orthogonal directions of samples processed by ECAP was characterized by tensile testing.


2007 ◽  
Vol 345-346 ◽  
pp. 597-600
Author(s):  
Duck Young Hwang ◽  
Kion Kwon ◽  
Dong Hyuk Shin ◽  
Kyung Tae Park ◽  
Young Gun Ko ◽  
...  

Ultrafine grained (UFG) 5083 Al and 5154 Al alloys were prepared by equal channel angular pressing (ECAP) with an effective strain of ~ 4 or ~ 8. This investigation was aimed at examining the effect of the ECAP strain and post-rolling inducing different microstructure in these alloys on the deformation mechanisms at low temperature superplastic (LTS) and high strain superplastic (HSRS) regimes. The sample after 4 passes (a strain of ∼ 4) did not exhibit LTS, but superplastic elongations were obtained in the sample after 8 passes (a strain of ∼ 8). An analysis of the mechanical data in light of the standard deformation mechanisms revealed that deformation of the sample after 4 passes was governed by dislocation climb while grain boundary sliding attributed to LTS of the sample after 8 passes. In addition, the 5154 Al alloy processed by ECAP and postrolling was capable of enhancing HSRS elongation significantly. An analysis revealed that the deformation mode was changed from dislocation viscous glide to grain boundary sliding by additional ECAP strain and post-rolling.


2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.


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