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1.
Effect of rotation speed on microstructure and mechanical properties of bobbin tool friction stir welded AZ61 magnesium alloy 总被引:2,自引:0,他引:2
L. Zhou G. H. Li G. D. Zha F. Y. Shu H. J. Liu J. C. Feng 《Science & Technology of Welding & Joining》2018,23(7):596-605
The 5-mm-thick AZ61 magnesium alloy was friction stir welded by using the specially designed bobbin tool with various rotation speeds. Defect-free welds were successfully obtained with rotation speed ranging from 550 to 600?rev?min?1. Grain size in different regions of the joints varied depending on the rotation speed. The hardness value of the joint is uniform. The defective joint fractured in the weld nugget zone with the lowest tensile strength, while the fracture location of the defect-free joints changed to the heat affected zone. The impact energy of weld nugget zone is higher than that of the heat affected zone, and the impact energy of the two zones in defect-free joint both decreased with increasing rotation speed. 相似文献
2.
La对AZ61镁合金组织及性能的影响 总被引:1,自引:0,他引:1
研究添加稀土La含量为(0,0.5,1.0,1.5)%对AZ61合金的微观组织及室温力学性能的影响.结果表明:加入0.5% ~1.5%的稀土后,铸态AZ61合金组织中的β-Mg17Al12相明显变得细小,形成了针状的Al11La3相.当稀土含量超过1.0%时,针状的Al11 La3相开始粗化长大,β-Mg17 Al12相的网状结构开始分离,变得细小;La的加入可以提高AZ61合金力学性能,当加入的La含量为1.0%时,AZ61合金的力学性能最好.因此,AZ61合金中加入La的质量分数为1.0%时,为合金化的最佳值. 相似文献
3.
Effect of La and Nd on microstructures and mechanical properties of AZ61 wrought magnesium alloy 总被引:1,自引:3,他引:1
Effects of La and Nd addition on the microstructure and mechanical properties of the AZ61 alloy have been investigated. The results show that when La and Nd are added into the AZ61 alloy respectively, the β(Mg17-Al12) phase is refined and granulated, and new phases are formed in the form of small rod-like shape, which are verified as La3 Al12 and Nd3Al11 phase by X-ray diffraction and TEM observation. Microstructure observations show that the effective efficiency of La addition is higher than that of Nd addition, thus the sizes of β(Mg17 Al12) and La3Al11 phase are relatively smaller than those of β(Mg17 Al12 ) and Nd3 Al11 phases in both AZ61 alloy and Nd-containing alloy. The increase of the tensile strength and elongation of AZ61 alloy refers to the existence of small rod-like La3Al11 and Nd3Al11 phases, and fine granulated β(Mg17 Al12 ) phase. 相似文献
4.
利用自行设计和研制的一套超声振动装置,试验研究超声导入温度、超声输出功率和超声处理时间对半固态AZ61镁合金微观组织的影响。试验结果表明,在半固态区间,只有将AZ61镁合金熔体控制在合适的温度时,才能获得细小、均匀的半固态球状组织;当超声振动时间为60 s时,对半固态AZ61镁合金超声处理的效果最好;随着超声振动功率的增加,熔体中的颗粒直径呈不断下降的趋势,晶粒尺寸得到的明显细化,形状趋于圆整。 相似文献
5.
对10mm厚板A231镁合金成功进行了搅拌摩擦焊接,获得成形良好、表面光滑、无裂纹、无气孔的焊接接头.研究该搅拌摩擦焊接头不同区域的显微组织特征,并通过拉伸、冲击和硬度试验分析了焊接接头的力学性能.结果表明,焊缝中心区是均匀细小的等轴晶粒,热力影响区晶粒大小不均匀,存在较明显的塑性流变带结构;焊接接头的抗拉强度达到母材的80%以上,焊接接头的冲击韧性比母材高,焊接接头的显微硬度比母材稍有降低,焊接接头具有较好的力学性能,说明搅拌摩擦焊是焊接厚板镁合金的一种有效方法. 相似文献
6.
To improve the strength, hardness and heat resistance of Mg-6Al-1Zn(AZ61) alloy, the effects of Pr addition on the as-cast microstructure and mechanical properties of AZ61 alloy were investigated at room and elevated temperatures by means of Brinell hardness measurement, optical microscope(OM), scanning electron microscope(SEM), energy dispersive spectroscopy(EDS), X-ray diffractometer(XRD) and DNS100 electronic universal testing machine. The results show that the microstructures of Pr-containing AZ61 alloys were refined, with primary β-Mg17Al12 phase distributed homogeneously. When the addition of Pr is up to 1.2wt.%, the β phase becomes fi ner, and new needle-like or short-rod shaped Al11Pr3 phase and blocky AlPr phase appear. As a result, optimal tensile properties are obtained. However, greater than 1.2wt.% Pr addition leads to poorer mechanical properties due to the aggregation of the needle-like phase and large size of grains. The present research fi ndings provide a new way for strengthening of magnesium alloys at room and elevated temperatures, and a method of producing thermally-stable AZ61 magnesium alloy. 相似文献
7.
Application of cyclic upsetting-extrusion to semi-solid processing of AZ91D magnesium alloy 总被引:1,自引:0,他引:1
Jian-quan TAO Ju-fu JIANG Hong CHEN Yuan-lun XIAO Rong-chao ZHANG Qing-hua HU Jun ZHAO Qiang ZHAO 《中国有色金属学会会刊》2013,23(4):909-915
The microstructural evolution of AZ91D magnesium alloy prepared by means of the cyclic upsetting-extrusion and partial remelting was investigated. The effects of remelting temperature and holding time on microstructure of semi-solid AZ91D magnesium alloy were studied. Furthermore, tensile properties of thixoextruded AZ91D magnesium alloy components were determined. The results show that the cyclic upsetting-extrusion followed by partial remelting is effective in producing semi-solid AZ91D magnesium alloy for thixoforming. During the partial remelting, with the increase of remelting temperature and holding time, the solid grain size increases and the degree of spheroidization tends to be improved. The tensile mechanical properties of thixoextruded AZ91D magnesium alloy components produced by cyclic upsetting-extrusion and partial remelting are better than those of the same alloy produced by casting. 相似文献
8.
An electromagnetic stirring process near liquidus temperature was designed and demonstrated experimentally to produce semi-solid slurry of AZ91 magnesium alloy, in order to avoid not only contamination from mechanical stirring but also the inflammation of Mg alloy melt at elevated temperature. AZ91 alloy feedstock was isothermally heat treated at 600-610 ℃ for 20 min, and then stirred by electromagnetic field. Globular primary particle characteristic was observed optically in the castings. Mechanical properties were also studied. 相似文献
9.
The effects of solution and aging treatments on the microstructures and mechanical properties of tungsten inert gas arc welded AZ61 magne-sium alloy joints were investigated by microstructural observations,microhardness tests and tensile tests.The results showed that the solution treatment led to the β-Mg17Al12 particles dissolved into the α-Mg grains.Hence,the microhardness of the fusion zone and the ultimate tensile strength of the welded joints were the lowest.With the increase of the aging temperature,the volume fraction of the β-Mg17Al12 particles in the fusion zone increased and this enhanced the microhardness of the fusion zone gradually.Also,the elongation of the welded joints was in-creased slightly with the increase of the volume fraction of the β-Mg17Al12 particles.However,the ultimate tensile strength of the welded joints increased at first and dropped at 190 ?C due to cracks formed at the boundaries of the β-Mg17Al12 particles. 相似文献
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轴向力对搅拌摩擦焊接AZ61A镁合金拉伸性能的影响(英文) 总被引:3,自引:0,他引:3
研究轴向力对搅拌摩擦焊接AZ61A镁合金拉伸性能的影响。在3~7kN范围内选择5个不同大小的轴向力制备接头。测试接头的拉伸性能,并研究其与搅拌区显微组织和硬度的相关性。结果表明,与其他轴向力下的接头相比,轴向力为5kN时制备的接头具有最好的拉伸性能。搅拌区生成的细晶组织和高硬度是获得高拉伸强度的主要原因。 相似文献
12.
Using friction stir processing to produce ultrafine-grained microstructure in AZ61 magnesium alloy 总被引:1,自引:1,他引:0
In order to obtain fine-microstructure magnesium alloys with superior mechanical properties, AZ61 alloy was processed by friction stir processing(FSP) combined with rapid heat sink. It is found that ultrafine-grained microstructure with average size less than 300 nm is observed in the resultant AZ61 alloy. The mean microhardness of the ultra-fine region reaches Hv 120-130, two times higher than that of AZ61 substrate. All these results demonstrate clearly that under a cooling rate high enough, ultra-free structure in AZ61 alloy with superior mechanical properties can be produced by one pass FSP via dynamic recrystallization. 相似文献
13.
Semisolid billet of AZ80 magnesium alloy was prepared by new strain induced melt activated (new SIMA) process and thixoforging experiment was performed. The results show that after as-cast AZ80 magnesium alloy is processed by equal channel angular extrusion, microstructure is refined well due to heavy dynamic recrystallization occurring in severe plastic deformation. Compared with semisolid isothermal treatment and conventional SIMA, semisolid billet with fine and spheroidal grains are achieved in new SIMA. Thixoforging process of semisolid billet prepared by new SIMA has many advantages such as good surface quality of final component, high ability to fill cavity and net-shape. The fine and spheroidal grains and high mechanical properties such as tensile strength of 298 MPa and elongation of 28% can be developed in final part thixoforged. 相似文献
14.
Effect of yttrium on microstructures and mechanical properties of hot rolled AZ61 wrought magnesium alloy 总被引:1,自引:0,他引:1
1 Introduction Magnesium alloys are attractive materials due to their good specific properties such as low density, good damping characteristics, good thermal conductivity and high elastic modulus[1,2]. Recently, there has been significant increase in the… 相似文献
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Rheo-diecasting of AZ91D magnesium alloy 总被引:1,自引:0,他引:1
A rheo-diecasting process (RDC) was investigated for semisolid processing of an AZ91D magnesium alloy. The results of the
RDC samples in as-cast state indicate that the microstructure of primary α-Mg particles has a fine size, nearly spherical
morphology, and uniform distribution throughout the components. Due to the advanced microstructure and reduced level of defects,
the RDC AZ91D Mg alloy exhibits an apparent improvement in mechanical properties. The quantitative metallographic investigations
reveal that increasing the intensity of forced convection during the slurry preparation results in a promoted nucleation and
reduced volume fraction of the primary phase solidified in the slurry maker. 相似文献
17.
在采用多道次搅拌摩擦加工成功地在镁合金表面覆合一层铝层的基础上,利用光学显微镜、透射电子显微镜、扫描电子显微镜、能谱分析和电子万能材料试验机对界面组织、元素成分分布、界面结合力和断口形貌进行了分析,并分析了不同焊接速度对重叠区界面组织和性能的影响规律.结果表明,界面由N道次区、重叠区和N+1道次区组成,重叠区界面过渡层的厚度随着焊接速度的降低而增加.其过渡层由Al+Al3Mg2相和Mg+Al12Mg17相组成.重叠区界面的剪切力随着速度的降低而增加,断裂方式为塑性断裂. 相似文献
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采用OM、XRD、SEM、EDS和高温拉伸试验机研究了不同Ho含量对AZ61合金的微观组织与力学性能的影响。结果表明,加入Ho能够细化基体组织,使β-Mg17Al12相由连续的网状变为断续的岛状和鱼骨状,但是加入量超过1.0%时,β相有重新结网的倾向,同时基体也有粗化的趋势。同时从基体中逐渐析出花瓣状的相,可以判断该相为Al-Mn-Ho的三元相。Ho的加入促进Al-Mn相的析出从而转化为三元相,随Ho的加入该相逐渐增多,并均匀分布在基体中和晶界处。同时随着Ho含量的增加,常温和高温下的力学性能都有了一定的改善。分析可知合金的抗拉强度σb、延伸率δ和韧性都在加入Ho量为1.0%时达到最大值分别为207.88 MPa、13.22%、11.5 J/cm2。当Ho含量为1.5%时合金的硬度达到了峰值为68.9 HB。当Ho加入量为1.0%时高温性能效果最佳,强度和延伸率分别为128 MPa、13.2%. 相似文献