Effect of nano-precipitation on thermal conductivity and mechanical properties of Mg-2Mn-xLa alloys during hot extrusion

Liu, Y.F.; Qiao, Xiaoguang; Li, Z.T.; Xia, Zehua; Zheng, M.Y.

doi:10.1016/j.jallcom.2020.154570

Cited by 24 publications

(8 citation statements)

References 30 publications

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“…The yield strength of the second phase is greater than the Mg matrix and can hinder the movement of dislocations. Therefore, the yield strength of the alloys increases with the second phase increasing [ 45 ]. However, as a hard and brittle phase, the second phase gradually presents a continuous network distribution along the grain boundary as the amount of La increases, which is not coordinated with the deformation of the Mg matrix during the tensile process and has a stronger cleavage effect on the matrix, which easily leads to the concentration of stress and the initiation of crack at the interface.…”

Section: Resultsmentioning

confidence: 99%

Effects of La Addition on the Microstructure, Thermal Conductivity and Mechanical Properties of Mg-3Al-0.3Mn Alloys

et al. 2022

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The effects of La addition on the microstructure, thermal conductivity and mechanical properties of as-cast and as-extruded Mg-3Al-xLa-0.3Mn (x = 1, 3 and 5 wt.%) alloys were studied. The results showed that the thermal conductivity of the alloys increased with the addition of La element, which was due to the formation of the Al11La3 phases by consuming the solute Al and the added La element. The yield strength of the as-cast Mg-3Al-xLa-0.3Mn alloys increased with the increase in La concentration. The thermal conductivity of the as-extruded alloys was lower than that of as-cast counterparts owing to lots of defects generated in the process of hot extrusion deformation, particularly the grain boundaries. The anisotropy of thermal conductivity was discovered in the as-extruded alloys on account of the formation of texture. As the La content increases, the tensile strength and yield strength of the as-extruded alloys decreased gradually. In contrast, the elongation first increased and then decreased, resulting from the combined effect of the texture strengthening and second phase strengthening.

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Section: Resultsmentioning

confidence: 99%

Effects of La Addition on the Microstructure, Thermal Conductivity and Mechanical Properties of Mg-3Al-0.3Mn Alloys

et al. 2022

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“…Because of the great differences in the atomic radius and elastic modulus of Zn, Gd, and Mg, they can create a better solid-solution strengthening effect [51]. The dispersed nano-scale precipitated phase particles in the E s 1.5 alloy can play a dominant role in strengthening the second-phase particles [52]. Therefore, the E s 1.5 alloy has better mechanical properties, and the change in the mechanical properties corresponds well with the change in fracture morphology.…”

Section: Stress Corrosion Crackingmentioning

confidence: 99%

Stress corrosion cracking behavior of an as-extruded Mg-1.8Zn-0.5Zr-1.5Gd magnesium alloy in a simulated body fluid

Yao¹,

Zha²,

Xiong³

et al. 2022

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The microstructure, corrosion resistance, and stress corrosion cracking behavior of an ascast and solid-solution Mg-1.8Zn-0.5Zr-1.5Gd biomagnesium alloy after extrusion deformation were studied. Results show that when the extrusion ratio was 7.7 and the extrusion temperatures were 350 and 360 • C, the as-cast and solid-solution alloys underwent complete dynamic recrystallization, and the grains were significantly refined. The precipitated phase in the extruded alloy is mainly composed of a nano-scale (Mg, Zn)3Gd and an Mg2Zn11 phase. A small amount of undissolved and broken micron-sized (Mg, Zn)3Gd phase particles appeared in the as-cast extruded alloy. The electrochemical corrosion produced during the stress corrosion process peeled off the (Mg, Zn)3Gd phase particles and induced rapid dissolution of the adjacent matrix. As a result, stresses were accumulated, and stress corrosion sensitivity occurred. At the same time, some larger-sized cracks appeared in the tensile fracture of the alloy. The difference in grain size and orientation in different regions of the solid-solution extruded alloy leads corrosion fracture to be composed of parallel grooves in different directions. Solution treatment of the magnesium alloy was found to reduce the stress corrosion susceptibility of extruded magnesium alloy and make it promising as a biodegradable implanting material.

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“…Heat treatment significantly influences the thermal conductivities of Mg alloys. For example, the room-temperature thermal conductivity of Mg-Al-Mn and Mg-Zn-RE alloys subjected to a solution treatment is lower than that of the as-cast alloys because of increase in the concentrations of solute atoms [11][12]. Yuan et al [9] studied the thermal characteristics of the as-cast and heat-treated (T6) Mg-Zn-Mn alloys and found that T6 aging treatment enhances thermal conductivity because of the decreased content of dissolved Zn through precipitation.…”

Section: Introductionmentioning

confidence: 99%

High thermal conductivity and high strength magnesium alloy for high pressure die casting ultrathin-walled components

Rong

Xiao

Zhao

et al. 2022

Int J Miner Metall Mater

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With the rapid development of 3C industries, the demand for high-thermal-conductivity magnesium alloys with high mechanical performance is increasing quickly. However, the thermal conductivities of most common Mg foundry alloys (such as Mg-9wt%-1wt%Zn) are still relatively low. In this study, we developed a high-thermal-conductivity Mg -4Al -4Zn -4RE -1Ca (wt%, AZEX4441) alloy with good mechanical properties for ultrathin-walled cellphone components via high-pressure die casting (HPDC). The HPDC AZEX4441 alloy exhibited a fine homogeneous microstructure (average grain size of 2.8 µm) with granular Al 11 RE 3 , fibrous Al 2 REZn 2 , and networked Ca 6 Mg 2 Zn 3 phases distributed at the grain boundaries. The room-temperature thermal conductivity of the HPDC AZEX4441 alloy was 94.4 W•m -1 •K -1 , which was much higher than 53.7 W•m -1 •K -1 of the HPDC AZ91D alloy. Al and Zn in the AZEX4441 alloy were largely consumed by the formation of Al 11 RE 3 , Al 2 REZn 2 , and Ca 2 Mg 6 Zn 3 phases because of the addition of RE and Ca. Therefore, the lattice distortion induced by solute atoms of the AZEX4441 alloy (0.171%) was much lower than that of the AZ91D alloy (0.441%), which was responsible for the high thermal conductivity of the AZEX4441 alloy. The AZEX4441 alloy exhibited a high yield strength of ~185 MPa, an ultimate tensile strength of ~233 MPa, and an elongation of ~4.2%. This result indicated that the tensile properties were comparable with those of the AZ91D alloy. Therefore, this study contributed to the development of high-performance Mg alloys with a combination of high thermal conductivity, high strength, and good castability.

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Effect of nano-precipitation on thermal conductivity and mechanical properties of Mg-2Mn-xLa alloys during hot extrusion

Cited by 24 publications

References 30 publications

Effects of La Addition on the Microstructure, Thermal Conductivity and Mechanical Properties of Mg-3Al-0.3Mn Alloys

Effects of La Addition on the Microstructure, Thermal Conductivity and Mechanical Properties of Mg-3Al-0.3Mn Alloys

Stress corrosion cracking behavior of an as-extruded Mg-1.8Zn-0.5Zr-1.5Gd magnesium alloy in a simulated body fluid

High thermal conductivity and high strength magnesium alloy for high pressure die casting ultrathin-walled components

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