Ce和Sb对Mg-3%Al合金铸态组织与力学性能的影响

研究了合金元素Ce和Sb对Mg-3%Al基合金显微组织和力学性能的影响。结果表明,Ce,Sb元素加入后使β-Mg17Al12相以细小弥散形态分布。只加入Ce元素时,Ce与合金中的Al元素形成针状的Al4Ce相,合金的铸态室温力学性能较Mg-3%Al合金更差;而Ce,Sb元素同时加入时,在基体中形成了弥散分布的CeSb颗粒相,同时抑制了针状的Al4Ce相的生成,合金表现出较好的强度和塑性。与Mg-3%Al合金相比,Mg-3%Al-1%Ce-1%Sb合金的铸态拉伸强度Rm提高了7.5%,伸长率A提高了91%。     

锑和稀土对Mg-9% Al-0.4% Zn合金铸态组织与力学性能的影响

锑和稀土均有细化Mg-9%Al-0.4%Zn合金铸态组织的作用，而且锑和稀土的同时加入，复合细化效果更显著，锑与合金中的镁元素形成短棒状的金属间化合物Mg3Sb2，稀土与合金中的铝元素形成片状金属间化合物Al11La3 和Al11Ce3。各相在a-Mg晶粒内和晶界均有分布，单独加入锑或稀土时对该合金的铸态室温力学性能基本没有影响，但同时添加0．8％RE和0．4％Sb时，合金的铸态室温力学性能显著提高，与Mg-9%Al-0.4%Zn合金相比，添加0.8%RE和0．4%Sb合金的铸态拉伸强度σb提高了33％，伸长率δ提高了70％，铸态Mg-9%AL-0.4%Zn-0.4%Sb-0.8RE拉伸断口具有明显的塑性变形特征。     

Sb对Mg-8Zn-4Al-0.3Mn合金显微组织的影响

试验研究了Sb对Mg-8Zn-4Al-0·3Mn铸造镁合金显微组织的影响。结果表明,含Sb铸造镁合金Mg-8Zn-4Al-0·3Mn-xSb的显微组织由基体α(Mg)、共晶[α(Mg) τ]、三元相τ(Mg32(Al,Zn)49、二元相MgZn2和Mg3Sb2组成;随着Sb含量的增加,合金晶界上三元相的形态逐渐由半连续网状变为分散均匀的颗粒状;w(Sb)=0.3%为最佳加入量,此时的合金铸态组织被明显细化,晶粒大小由120μm~130μm减小到50μm~60μm。同时,合金的显微硬度值也随Sb含量的增加而增加。     

Sb对Mg-6Al合金显微组织及其焊丝力学性能的影响

研究了合金元素Sb对Mg-6Al合金的铸态显微组织及热挤压镁合金焊丝力学性能的影响。研究结果表明，Sb对Mg-6Al合金的铸态组织有明显的细化作用，细化了α-Mg晶粒和Mg17-Al12相，Sb与元素Mg形成短棒状的金属间化合物Mg3Sb2，该相在α-Mg晶粒内和晶界均有分布。当添加质量分数为1．0％的Sb时，合金铸态组织的细化效果最为显著。另外，添加合金元素Sb，对提高Mg-6Al合金焊丝的力学性能有显著效果，当加入质量分数为1.0％的Sb时，焊丝的抗拉强度σb最高，为334．6MPa，伸长率δ为14．54％，与Mg-6Al相比，σb与δ分别提高61％与37％。     

Al5TiB、RE对Mg-8Zn-4Al-0.3Mn合金显微组织和时效过程的影响

研究Al5TiB、RE对Mg-8Zn-4Al-0.3Mn铸造镁合金显微组织、时效过程的影响.结果表明:加入Al5TiB的Mg-8Zn-4Al-0.3Mn合金的显微组织主要由Mg相、φ(Al2Mg5Zn2)相、τ(Mg32(Al,Zn)49)相组成.晶粒大小可由120～130 μm减少到30～40 μm.加入RE的Mg-8Zn-4Al-0.3Mn-xRE合金的显微组织主要由Mg相、φ(Al2Mg5Zn2)相、τ(Mg32(Al,Zn)49)相和Mg3Al4Zn2RE相组成.晶粒大小由120～130 μm减少到40～50 μm.合金的显微硬度值随RE加入量的增加而增加.随着Ti元素在合金中含量的增加,合金的析出相形成激活能呈先增大后减小的变化规律,而含RE元素合金的析出相形成激活能则随RE元素加入量的增大而增大.     

RE对Mg-8Zn-4Al-0.3Mn合金组织的影响

研究了RE对Mg-8Zn-4Al-0．3Mn铸造镁合金显微组织的影响。结果表明：Mg-8Zn-4Al-0．3Mn-χRE铸造镁合金的显微组织主要由口(Mg)基体、φ(Al2Mg5Zn2)相、r(Mg32(Al,Zn)49)相和Mg3Al4Zn2RE相组成。随RE加入量的增加，合金晶界上三元相的形态由半连续网状改变为颗粒状，三元相的分布逐渐变得弥散而均匀。晶界上针状或棒状Mg3Al4Zn2RE相的量也随着RE加入量的增加而增加。加入1．5％的RE可显著细化合金的铸态组织，晶粒大小由120～130μm减小到40-50μm。合金的显微硬度值随着RE加入量的增加而增加。     

Sb含量对铸态Mg-4Al-1Zn-1Si合金组织与性能的影响

研究了合金元素Sb对Mg-4Al-1Zn-1Si合金组织和性能的影响.结果表明:加入0.25wt％Sb时,合金中形成了Mg3Sb2相,原来大量聚集于晶界的粗大汉字状Mg2Si相颗粒转变为相对细小的汉字状Mg2Si相颗粒,呈弥散分布于晶界及晶内,同时出现了少量多边形块状Mg2Si相颗粒,此时合金的力学性能有所提高;当Sb为0.5％时,Mg2Si相颗粒尺寸迅速减小,转变为球状或短棒状,此时,合金的室温和高温抗拉强度、屈服强度和伸长率均达到最大值;当Sb含量为0.75％时,Mg2Si相颗粒尺寸未见明显变化,但又发生聚集现象;当Sb含量为1.0％时,Mg2Si相颗粒又转变为尺寸较大的汉字状颗粒,此时合金的力学性能发生下降.     

等温热处理工艺参数对Mg-8%Al-1%Si合金半固态显微组织的影响(英文)

采用等温热处理工艺制备具有半固态显微组织的Mg-8%Al-1%Si合金,研究等温热处理工艺参数(等温温度和等温时间)对Mg-8%Al-1%Si合金显微组织的影响。结果表明:通过等温热处理工艺可以得到具有非枝晶组织的Mg-8%Al-1%Si合金。随着等温温度从560°C升高至575°C或等温时间从5min延长至30min,半固态组织中的液相体积分数增加,α-Mg晶粒尺寸变大并且其球化趋势明显。此外,在半固态组织中的共晶Mg2Si相从汉字状转变成为颗粒状。研究等温热处理Mg-8%Al-1%Si合金中的共晶Mg2Si相的形貌转变机制。     

Sb含量对Mg-4Zn-Y合金组织和性能的影响

利用OM,SEM,XRD及力学性能测试等手段,研究了Sb含量对Mg-4Zn-Y合金组织及性能的影响。结果表明,含Sb铸造镁合金Mg-4Zn-Y-xSb的显微组织由基体α(Mg)、二元共晶相Mg7Zn3、三元相I(Mg3Zn6Y)和YSb组成,随着Sb含量的增加,合金晶界上二元共晶相Mg7Zn3的形态逐渐由半连续网状变为分散均匀的颗粒状。合金的拉伸强度、塑性和硬度随Sb含量的增加而提高,但Sb含量过大时合金的综合力学性能下降。     

微量元素Ce／Sb及时效处理对AZ91D合金显微组织及力学性能的影响

研究了时效处理对添加Ce/Sb的AZ91D合金显微组织、力学性能的影响。结果表明,添加Ce和Sb后,β-Mg17Al12变为断续网状或粒状分布,数量也相对减少,并形成弥散分布的Mg3Sb2、CeSb、Al11Ce3新相。时效处理后,试验合金晶界变得模糊,随时效过程进行,新相逐渐析出,最终在时效处理为200℃×12h时形成稳定的颗粒状或短棒状析出相;220℃×12h时效处理后,析出相已经开始聚集、长大,成为条状相。时效处理后,合金维氏硬度提高,在220℃×12h时,维氏硬度达HV97,同比铸态提高37%。     

Effects of Ce and Sb on the microstructure and properties of AZ91D magnesium alloy prepared by the EPC process

The effects of small amounts of cerium and antimony additions on the microstructure and the mechanical properties of AZ91D（Mg-9Al-Zn） based alloy were researched via the expendable pattern casting（EPC） process.The results show that the microstructure is obviously refined and the tensile strength of the AZ91D based alloy at ambient temperature is significantly improved.When compared to AZ91D,the AZ91D-1.0?-0.4%Sb alloy has higher ultimate tensile strength and elongation.Its ultimate tensile strength and elongation are enhanced by 39% and 47%,respectively.The morphology of the tensile fracture of the AZ91D-1.0?-0.4%Sb alloy has more characteristics of quasi-cleavage.This indicates that it has had a larger plastic deformation before failure.The tensile strength and elongation decrease with the increase of Ce and Sb contents because of the coarsening and volume increase of CeSb and Al11Ce3 phases.     

Characteristics of plasma electrolytic oxide coatings on Mg-Al-Zn alloy prepared by powder metallurgy

Mg-6 wt.%Al-1 wt.%Zn alloy powders were produced by gas atomization, and subsequently compacted and sintered under various conditions of temperature, time, and pressure. The bulk Mg-6 wt.%Al-1 wt.%Zn alloy was coated by the plasma electrolytic oxidation (PEO) method. The optimum condition of compaction and sintering for PEO coatings was established based on the investigation of microstructure, microhardness, and corrosion properties of coatings which were compared to those of cast Mg-6 wt.%Al alloy. The coatings on Mg-6 wt.%Al and Mg-6 wt.%Al-1 wt.%Zn alloys consisted of MgO, MgAl₂O₄, and Mg₂SiO₄. The Mg-6 wt.%Al-1 wt.%Zn alloy compacted at room temperature for 10 min and sintered at 893 K for 3 h showed the most porous and nonuniform coating layer because the coatings had grown through grain boundaries that resulted from poor bonding between powder particles in the substrate. However, the coated Mg-6 wt.%Al-1 wt.%Zn alloy hot-compacted at 593 K for 10 min had the thickest coating layer and the highest microhardness. In addition, it demonstrated the best corrosion resistance as verified by polarization curves in 3.5% NaCl solution.     

快速凝固制备Mg-Al-Zn合金薄带

镁合金的力学性能、抗腐蚀性能及室温塑性都较差,至今它的应用仍受到限制。快速凝固通过改善合金的微观结构,是克服上述局限的有效方法之一。采用双辊旋铸技术快淬制备AZ31镁合金薄带。对双辊转速对薄带厚度及其微观硬度的影响进行了分析。微观硬度随双辊转速的提高而提高。然而,由于AZ31镁合金的Al、Zn含量过少,固溶有限,所以由热处理引起的析出相强化有限,这也是由热处理所引起的微观硬度增幅不大的原因。所以,对AZ31镁合金进行强化处理,应该采用快速凝固细化晶粒的方法较为有效。     

Sb对过共晶Mg-4.8%Si合金中Mg_2Si初晶变质的影响

利用Mg-20%Sb中间合金对过共晶Mg-4.8%Si合金进行变质处理,考察Sb的含量对Mg2Si初晶变质效果(主要包括形态和尺寸)的影响规律,并讨论其变质机制。结果表明:Sb的加入量是决定其能否有效变质过共晶Mg-4.8%Si合金中Mg2Si初晶的重要因素;在未变质的过共晶Mg-Si合金中,Mg2Si初晶以粗大的树枝晶状为主;当Sb加入量低于0.8%(质量分数)时,Mg2Si初晶形态无明显改善,其平均尺寸略有降低;当Sb加入量达到并超过1.2%后,Sb才能有效变质过共晶Mg-4.8%Si合金中Mg2Si初晶,且Mg2Si初晶呈细小的颗粒状弥散分布,其平均尺寸迅速减小;其变质机制应与残留在熔体中弥散分布的Mg3Sb2粒子作为Mg2Si初晶的形核核心有关。     

Sb effect on micro structural and mechanical properties of rapidly solidified Al-12Si alloy

The effects of antimony (Sb) addition on the microstructure and mechanical properties of rapidly solidified eutectic Al-Si alloy were investigated. Al-12 wt.%Si-X wt.%Sb (X = 0, 0.5 and 1.0) alloys were fabricated using a melt-spinner at rotating speeds of 20 m/s. The as-melt-spun ribbons were characterized by a combination of scanning electron microscopy (SEM), X-ray diffraction (XRD) and depth-sensing indentation (DSI) methods. SEM observations showed that 0.5%Sb addition refined the microstructure whereas 1.0%Sb addition led to the formation of coarse Si particles. The wheel side of the ribbons exhibited a finer microstructure than those on the free or air sides exposed to the atmosphere. According to the XRD results, the diffraction patterns of melt-spun ribbons consisted solely of α-Al and Si phases, and a possible volume fraction of AlSb or an intermetallic phase in the alloy was not observed. DSI tests were performed on the ribbons under different loads ranging from 200 to 1200 mN at room temperature. The resulting indentation load-displacement (P-h) curves were analyzed using the work of indentation approach (WIA) to evaluate the ribbons’ microhardness (H) and reduced modulus (Er). We found that the H and Er values of the ribbon decrease with increasing Sb content. This can be attributed to the over modification and changes in the microstructure of Al-12%Si alloy when a minimum of 1.0%Sb is present as a modifier.     

Mg-(6～8)Al-1Zn-0.7Si-0.25Mn镁合金的DSC分析

采用DSC差热分析方法,研究了Sb和RE复合添加以及Al含量变化对Mg-（6～8）A1-1Zn-0.7Si-0.25Mn合金DSC曲线的影响。结果表明：同时添加0.4%Sb和0.25%RE,Mg-6A1-1Zn-0.7Si-0.25Mn合金的凝固峰值温度、凝固开始温度和凝固结束温度下降,凝固温度范围扩大,而对于添加了0.4%Sb和0.25%RE的Mg-（6～8）A1-1Zn-0.7Si-0.25Mn合金,随Al含量增加,合金的凝固开始温度和凝固结束温度下降,凝固温度范围扩大,但凝固峰值温度变化不大。     

时效对挤压变形Mg-6%Al-0.5%Ni合金组织与性能的影响

通过显微组织观察、拉伸性能测试及断口分析,研究了时效处理对挤压变形Mg-6%Al-0.5%Ni合金显微组织及拉伸性能的影响.结果表明,挤压变形Mg-6%Al-0.5%Ni合金时效后,强化相粒子可在晶界处以及晶粒内部析出,有效地提高其高温屈服强度和抗拉强度,但导致合金的伸长率降低;合金的拉伸断口呈现韧性和脆性混合断裂特征,而挤压态Mg-6%Al-0.5%Ni合金的拉伸断口均呈现典型的韧性断裂特征.     

微量Sb对Mg-7Gd-3Y铸态合金组织及力学性能的影响

利用光学显微镜、扫描电镜和X射线衍射仪,分析研究了微量Sb对Mg-7Gd-3Y铸态合金组织及其室温和高温力学性能的影响。结果表明,在合金中加入1%的Sb,促进了新的颗粒相Gd5Sb3和Y3Sb产生,使晶粒细化;合金的室温和高温抗拉强度分别提高了3.3%和5.3%;屈服强度分别提高了12.8%和17.0%;伸长率分别降低了15.8%和12.3%。     

Microstructures and mechanical properties of Mg-10Ho-0.6Zr-xNd alloys

Mg-10Ho-0.6Zr-xNd (x=0, 1, 3 and 5, mass fraction, %) alloys were prepared by metal mould casting, and the microstructures and mechanical properties were investigated. The results show that the grain size of as-cast alloys reduces and the hardness and strength increase with the increase of Nd content. The alloys are aged followed by solid solution treatment. Mg-10Ho-0.6Zr-3Nd and Mg-10Ho-0.6Zr-5Nd alloys exhibit obvious age hardening response. The hardness value of Mg-10Ho-0.6Zr-5Nd alloy increases from HV104 at as-cast state to HV136 at peak-aged state. The maximum ultimate tensile strength and yield strength of the Mg-10Ho-0.6Zr-5Nd alloy are obtained in at peak-aged state, and the values are 323 MPa, 212 MPa at room temperature, and 258 MPa, 176 MPa at 250 ℃, respectively. The improvement of the tensile strength is mainly attributed to the fine and dispersively distributed plate-shaped β′ metastable phase.