Multimodal Microstructure and Mechanical Properties of AZ91 Mg Alloy Prepared by Equal Channel Angular Pressing plus Aging

Yang, Zhen; Ma, Aibin; Liu, Huan; Sun, Jiapeng; Song, Dandan; Wang, Ce; Yuan, Yong; Jiang, Jinghua

doi:10.3390/met8100763

Cited by 37 publications

(9 citation statements)

References 52 publications

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“…In general, the microstructure of the alloy after aging had a lower dislocation density, both in the grain body and in the boundary areas. Thus, our results are consistent with the grain refinement found during the aging process of the ECAP-treated samples and reported in reference 24 . The formation of a large number of dispersed Al20Cu2Mn3 particles, mainly located along the grain boundaries but also present in the body of a grain, is observed.…”

Section: Aging Effect On the Deformed Microstructuresupporting

confidence: 93%

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

Andreyachshenko¹,

Isheva²,

Mazhit³

et al. 2019

Mater. Tehnol.

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The work deals with the effect of the ECAP treatment on the microstructure and mechanical properties of the AA2030 alloy. There were four cycles of deformation in the 105°-tool for pre-annealed samples, which ensured the preparation of an ultrafine-grained structure, both along the Bc route and along the C route. The average grain size after four cycles of ECAP was 420 nm for the samples treated along the Bc route and 380 nm for the samples treated along the C route. In the structure of the metal, there were inclusions of Al20Cu2Mn3, the q-phase and Al7Cu3Fe. After three cycles of the ECAP treatment, the alloy was hardened by 54 % along the Bc route and 60 % along the C route compared with the annealed condition. The overall increase in the microhardness was 138 % for the samples treated along the Bc route and 113 % for the samples treated along the C route. Because of prolonged aging, the number of dispersoids increased at room temperature, long rod-like inclusions transformed into more favourable short ones with a length of up to 150 nm, and partial dissolution of the q-phase was observed. After the aging, the grain boundaries were predominantly equilibrium, thin, without the moire contrast, and a rearrangement of dislocation walls into subgrain boundaries was found. In addition, after the prolonged natural aging, large grains with non-equilibrium boundaries fragmented into subgrains with sizes of 100-300 nm.

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Section: Aging Effect On the Deformed Microstructuresupporting

confidence: 93%

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

Andreyachshenko¹,

Isheva²,

Mazhit³

et al. 2019

Mater. Tehnol.

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“…The diffraction patterns exhibit near-ring characteristic, and index of the diffraction rings demonstrates that the precipitates are Mg 17 Al 12 phases. The Mg 17 Al 12 precipitates are usually reported in AZ91 alloys [36]. As for Mg-Al-Ca alloys, Al 2 Ca phase served as the main precipitates during hot deformation or aging in most cases [24], and precipitation of Mg 17 Al 12 particles was barely reported.…”

Section: Methodsmentioning

confidence: 99%

Improving Strength and Ductility of a Mg-3.7Al-1.8Ca-0.4Mn Alloy with Refined and Dispersed Al2Ca Particles by Industrial-Scale ECAP Processing

Sun

Zhuo

et al. 2019

Metals

Self Cite

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Tailoring the morphology and distribution of the Al2Ca second phase is important for improving mechanical properties of Al2Ca-containing Mg-Al-Ca based alloys. This work employed the industrial-scale multi-pass rotary-die equal channel angular pressing (RD-ECAP) on an as-cast Mg-3.7Al-1.8Ca-0.4Mn (wt %) alloy and investigated its microstructure evolution and mechanical properties under three different processing parameters. The obtained results showed that RD-ECAP was effective for refining the microstructure and breaking the network-shaped Al2Ca phase. With the increase of the ECAP number and decrease of the processing temperature, the average sizes of Al2Ca particles decreased obviously, and the dispersion of the Al2Ca phase became more uniform. In addition, more ECAP passes and lower processing temperature resulted in finer α-Mg grains. Tensile test results indicated that the 573 K-12p alloy with the finest and most dispersed Al2Ca particles exhibited superior mechanical properties with tensile yield strength of 304 MPa, ultimate tensile strength of 354 MPa and elongation of 10.3%. The improved comprehensive mechanical performance could be attributed to refined DRX grains, nano-sized Mg17Al12 precipitates and dispersed Al2Ca particles, where the refined and dispersed Al2Ca particles played a more dominant role in strengthening the alloys.

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“…The eutectic β-phases were dissolved into the matrix and more equiaxed grains were developed by T4 treatment, which improved the elongation of the alloy. After T6 treatment, profuse lamellar DPs and a small amount of finer CPs precipitated along the grain boundaries and interiors, playing a vital role in the phase-hardening behavior by the Orowan mechanism [32,33], and thus significantly improving the mechanical properties of the extruded alloy. To further clarify the performance difference of extruded alloy in different states, the SEM microstructure near the fracture surface of extruded, T4, T5, and T6 specimens is given in Figure 10.…”

Section: Effect Of Heat Treatment On Microstructurementioning

confidence: 99%

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

Zhao

Yan

et al. 2019

Materials

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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.

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Multimodal Microstructure and Mechanical Properties of AZ91 Mg Alloy Prepared by Equal Channel Angular Pressing plus Aging

Cited by 37 publications

References 52 publications

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

ECAP-treated aluminium alloy AA2030: microstructure and mechanical properties

Improving Strength and Ductility of a Mg-3.7Al-1.8Ca-0.4Mn Alloy with Refined and Dispersed Al2Ca Particles by Industrial-Scale ECAP Processing

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

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