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Microstructures and mechanical properties of AZ80 alloy treated by pulsed ultrasonic vibration 总被引:1,自引:0,他引:1
Pulsed ultrasonic field was employed in the melt of the AZ80 magnesium alloy.The effects of pulsed ultrasonic field on microstructure and mechanical properties of AZ80 magnesium alloy were investigated.The results show that the as-cast microstructure of the AZ80 alloy with pulsed ultrasonic treatment is significantly changed.Pulsed ultrasonic field significantly decreases the grain size,changes the morphologies of theβ-Mg_(17)Al_(12) phases and reduces their area fraction.It is found that pulsc width of ... 相似文献
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研究不同Sr含量(0,0.3%,2.5%和5.0%,质量分数)的AZ31镁合金的铸态组织及含锶相。结果表明:在AZ31镁合金中添加Sr后,枝晶/晶粒尺寸变小,并且在0~5.0%的范围内,随着Sr含量的增加,枝晶细化且形态出现钝化现象,位于晶界/枝晶界的合金相分布更加弥散。添加0.3%Sr后,β-Mg17Al12相从未添加Sr的AZ31合金中的连续、不规则条状转变为不连续、不规则条状和/或细小颗粒状。在添加2.5%Sr和5.0%Sr的合金中发现了一些层片状共晶相,且后者的层片间距更加小。较高含量的Sr添加到AZ31镁合金中可以形成一种新的共晶和/或离异共晶三元Mg11Al5Zn4相,在添加2.5%Sr和5.0%Sr的合金中发现了Mg17Sr2相和Mg2Sr相。 相似文献
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AZ80 magnesium alloys were deformed at 200,250,300,350 and 400℃ with different deformation degree of 50%,75%, 83%,87%and 90%,respectively.The corrosion properties of different deformed AZ80 samples were studied by galvanic test in 3.5%NaCl solution.The results show that plastic deformation could improve the corrosion resistance of AZ80 alloy;and the corrosion rate of AZ80 deformed at 250℃ with the deformation degree of 83%was the lowest,which was 33%of the as-cast AZ80 alloy.Further studies of the microstructure show that the refined grain size and continuously distribution ofβphase around the grain boundary did have a positive effect on the improvement of corrosion resistance of AZ80 alloys.For AZ80 alloys,the smaller the grain size is,the more homogeneous the structure is,and the better the corrosion resistance is. 相似文献
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Effect of high-intensity ultrasonic field on process of semi-continuous casting for AZ80 magnesium alloy billets 总被引:2,自引:0,他引:2
Under the high-intensity ultrasonic field,AZ80 magnesium alloy was semi-continuously cast.The effects of ultrasonic intensity on the as-cast microstructures and mechanical properties were investigated.The results show that the microstructures of the alloy cast under high-intensity ultrasonic field are fine and uniform,and the grains are equiaxed,rose-shaped or globular with an average size of 257μm.High-intensity field significantly decreases the grain size,changes the morphologies of theβ-Mg17Al12 phases and reduces their area fraction.It is also shown that a proper increase in ultrasonic intensity is helpful to obtain fine,uniform and equiaxed as-cast microstructures.The optimum ultrasonic parameters are that frequency is 20 kHz and ultrasonic intensity is 1 368 W.The mechanical tests show that the mechanical properties of the as-cast AZ80 magnesium alloy billets cast under ultrasonic field are greatly improved,and with increasing the ultrasonic intensity,the mechanical properties of the entire alloy billets are much higher and more uniform than those of the alloy without ultrasonic field. 相似文献
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为选择一种高性价比的镁电池阳极材料,借助电化学工作站、光学显微镜(OM)、扫描电子显微镜(SEM)和X射线能谱分析(EDS)对不同加工状态的AZ31B镁合金电化学性能进行研究。分别将挤压、轧制、铸轧和铸态AZ31B镁合金作为阳极材料,测试其电化学性能。结果表明,在4种加工状态下,挤压态镁合金是性价比最高的一种阳极材料;其组织由均匀细小的晶粒和第二相组成,拥有最负的平衡电位,最低腐蚀电流密度和最小自腐蚀速率;挤压态样品腐蚀后,表面产生疏松细小,且均匀分布的腐蚀产物,降低了阳极极化,增加了阳极利用率。轧制和铸轧态的AZ31B镁合金的电化学活性和耐蚀性能相对挤压态的较低。铸态AZ31B镁合金由于较粗大的晶粒、第二相和铸造缺陷,表现出不稳定的放电曲线和较正的放电电位。不同状态AZ31镁合金的腐蚀均以点蚀为主。 相似文献
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对比了相控阵超声和常规超声对接焊缝的检测仿真和试验,分析了对接焊缝相控阵超声检测的可靠性,为承压设备相控阵超声检测标准的制订提供相应参考。仿真与试验得出:相控阵超声检测的缺陷检出率总体上要高于常规超声检测。对于有着严重危害且对声束指向性要求较高的面状缺陷,相控阵超声的检出率要高于常规超声。对于夹渣、未焊透等体积性缺陷,相控阵与常规超声的检出率均非常高。但是对于气孔类回波较小的体积性缺陷,相控阵超声的检出率明显高于常规超声。对于工件厚度较大的焊缝,相控阵超声较常规超声技术可以扫描检测到更厚的焊缝区域。在缺陷测长方面,相控阵超声的测长结果相对于常规超声技术总体偏大,测长精度并无明显优势。 相似文献
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针对扩散连接界面缺陷的无损检测问题,开展了人工缺陷试样的水浸超声检测试验研究,提出了扩散连接界面缺陷超声响应模型,开发了一种通过超声检测评估界面缺陷厚向尺寸的检测手段. 首先利用扩散连接的方法制备了带有人工缺陷扩散连接试样,采用30 MHz的入射波频率,对试样进行水浸超声无损检测. 基于超声无损检测原理提出了未焊合缺陷的超声响应模型,引入扩散连接界面劲度系数K作为桥梁建立起超声反射波反射率与界面缺陷尺寸之间的联系. 通过特定检测位置的超声反射波数据和实际微观缺陷尺寸数据拟合确定超声响应模型常数,进而实现基于超声无损检测的界面缺陷厚向尺寸评估. 结果表明,传统超声C扫描一般只是定性地反映缺陷存在与否,而厚向尺寸评估方法的提出在一定程度上为超声C扫描做了补充,有助于缺陷尺寸的定量检测,实现缺陷危害等级的评估. 相似文献
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The flow stress of magnesium alloys during hot compression at different temperatures and strain rates was studied by experiments.Materials used were AZ91D alloys in as-cast,homogeneous treatment states,AZ31 and ZK60 alloys in as-cast state. The results show that the thermal simulation curves of different alloys differ from one another at the same deforming condition.The general curves of AZ31 and AZ91D alloys have the character of dynamic recrystallization.There are increase of true stress,drastic fallin... 相似文献
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为了确保激光增材制件的质量安全,对其进行可靠的无损检测与评价尤为重要。 针对 TA15 钛合金激光熔化沉积制件,使用常规超声以及超声相控阵检测技术对其内部缺陷进行检测,重点研究了激光增材制件内部缺陷的超声检测特性以及超声相控阵检测技术在增材制件上的应用优势。 使用激光熔化沉积技术制备了含有熔合不良缺陷的试验样件,从 XYZ 3 个方向分别对样件进行了全面检测。 结果表明,激光增材制件内部的缺陷具有明显的方向性,因此, 为了确保激光增材制件检测结果可靠,应从 XYZ 3 个方向分别进行全面检测。 相比与常规超声检测,超声相控阵检测技术大大提高了检测效率,能够直接成像缺陷的轮廓边界,降低了技术依赖性及人工疲劳性,针对大型增材制件的检测需求具有广阔的应用前景。 相似文献
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Nd添加对AZ80镁合金显微组织及力学性能的影响(英文) 总被引:3,自引:0,他引:3
研究添加稀土元素Nd对AZ80镁合金显微组织及力学性能的影响。结果表明:添加1.0%Nd元素可以有效地改善AZ80合金的铸态组织,其晶粒尺寸由448μm细化至125μm,凝固组织中出现条状的Al11Nd3相和块状的Al2Nd相,且β-Mg17Al12相显著细化,由连续网状变为不连续分布。时效过程中Nd元素的添加抑制了晶界处不连续析出相的出现,并推迟合金时效峰值的出现。在AZ80合金中添加1.0%Nd时,合金的综合力学性能最佳,屈服强度、抗拉强度和伸长率分别为103.7MPa、224.0MPa和8.4%。该合金T6态的屈服强度和抗拉强度分别达到141.1和231.1MPa。 相似文献
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K.B. Nie X.J. Wang K. WuL. Xu M.Y. ZhengX.S. Hu 《Journal of Alloys and Compounds》2011,509(35):8664-8669
Particulate reinforced magnesium matrix nanocomposites were fabricated by semisolid stirring assisted ultrasonic vibration. Compared with the as-cast AZ91 alloy, the grain size of matrix alloy in the SiCp/AZ91 nanocomposite stirring for 5 min was significantly decreased due to the addition of SiC nanoparticles. SiC nanoparticles within the grains exhibited homogeneous distribution although some SiC clusters still existed along the grain boundaries in the SiCp/AZ91 nanocomposite stirring for 5 min. With increasing the stirring time, agglomerates of SiC nanoparticles located along the grain boundaries increased. The ultimate tensile strength, yield strength and elongation to fracture of the SiCp/AZ91 nanocomposite stirring for 5 min were simultaneously improved compared with the as-cast AZ91 alloy. However, the ultimate tensile strength and elongation to fracture of the SiCp/AZ91 nanocomposite decreased with increasing the stirring time. 相似文献
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喷射成形Mg-9Al-xZn合金的微观组织演变 总被引:1,自引:0,他引:1
利用喷射成形技术制备AZ91、AZ92和AZ93镁合金沉积柱坯,并对其微观组织演变进行观察.结果表明:铸态普通凝固AZ91合金的晶粒粗大,脆性β-Mg17Al12相连续分布成网状结构;而喷射成形AZ91、AZ92和AZ93合金的组织均匀,晶粒被充分细化,β-Mg17Al12相的网状结构被打破;喷射沉积快速凝固条件下高的冷却速率促进了过饱和α-Mg固溶体组织的形成,使得偏析相减少,形态改善;Zn含量的增加降低了Al在Mg中的溶解极限,促进了β-Mg17Al12相在晶界的析出及α-Mg+β-Mg17Al12离异共晶组织的形成;Zn元素的偏析倾向为激活成分过冷区内的形核质点提供了驱动力,从而阻碍了晶粒长大. 相似文献
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Microstructure observation and dynamic mechanical analysis were carried out to investigate the precipitation and responding damping behaviors of AZ31 magnesium alloy. All the strain amplitude-dependent damping curves of the aged alloys are located between the curves of solutionized and as-cast alloys, although they have different critical strain amplitudes. The G-L theory is employed to explain the damping mechanism involving the interaction between the dislocation and the precipitated phase. In addition, a damping peak is observed at temperatures close to 330 ℃ for AZ31 magnesium alloy, which is related to the β-Mg17Al12 phase dissolution. 相似文献