Effect of Icosahedral Quasicrystalline Fraction and Extrusion Ratio on Microstructure, Mechanical Properties, and Anisotropy of Mg-Zn-Gd-Based Alloys
Effect of Icosahedral Quasicrystalline Fraction and Extrusion Ratio on Microstructure, Mechanical Properties, and Anisotropy of Mg-Zn-Gd-Based Alloys
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DOI：
10.1007/s11661-013-1609-y
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发表时间：
2013-01
期刊：
影响因子：
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通讯作者：
Hua Huang;G. Yuan;Zhongchang Wang;Chunlin Chen;W. Ding
中科院分区：
文献类型：
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作者：
Hua Huang;G. Yuan;Zhongchang Wang;Chunlin Chen;W. Ding
我们制备了三种含有二十面体准晶相（I相）的Mg-Zn-Gd基合金，研究了I相的体积分数和挤压比对挤压态合金的显微组织、力学性能和各向异性的影响。结果表明，随着I相体积分数的增加和挤压比的增大，合金的晶粒得到细化，抗拉强度和伸长率提高，这是由于第二相粒子促进再结晶形核和抑制晶界运动的结果。此外，各向异性减轻在所有的合金中，无论是I相的分数或挤压比增加，由于织构弱化和晶粒细化的共同作用，以及对孪生的I相的效果。随着I相含量的增加，低比挤压合金的屈服强度降低，这是由于织构弱化;而高比挤压合金的屈服强度提高，这是由于I相的强化和晶粒细化。高挤压比合金的力学性能得到提高，这是由于其晶粒细小，组织均匀。
We have fabricated three types of Mg-Zn-Gd-based alloys containing the icosahedral quasicrystalline phase (I-phase) to investigate how volume fraction of the I-phase and extrusion ratio can have an impact on the microstructure, mechanical properties, and anisotropy of the as-extruded alloys. We find that grains are refined and that the ultimate tensile strength and elongation are improved as either the volume fraction of I-phase or the extrusion ratio is increased, which can be attributed to the secondary phase particle stimulate recrystallization nucleation and restrained grain boundary motion. Moreover, anisotropy is mitigated in all of the alloys as either the I-phase fraction or the extrusion ratio is increased owing to the coeffect of texture weakening and grain refinement as well as to the effect of I-phase on twinning. We also find that with the increase in the amount of the I-phase, the yield strength (YS) is decreased for the alloys extruded at a low ratio owing to the texture weakening, yet it is increased for the alloys extruded at high ratio owing to the strengthening originating from the I-phase and refined grains. The mechanical properties are improved for the alloys extruded at high ratio, which is due to their fine grains and uniform microstructure.