电脉冲孕育处理对Al-15Mg_2Si-1Cu合金组织和性能的影响

研究了电脉冲处理参数对Al-15Mg2Si-1Cu合金组织和性能的影响。结果表明,电脉冲处理能够明显减小初生Mg2Si相的尺寸;与未脉冲处理时相比,脉冲处理后Mg2Si相尺寸降低约60%,其中当脉冲电压为500 V时,Mg2Si尺寸最小,约为10μm~30μm;电脉冲处理仅改变了Al-15Mg2Si-1Cu合金中相的形状、尺寸、分布,未改变其相组成;经过电脉冲处理后的Al-15Mg2Si-1Cu合金的力学性能较好,当脉冲电压为500 V时抗拉强度最高,伸长率最高。     

Al-1B变质处理对Zn-6Al-3Mg合金凝固组织与性能的影响

采用扫描电镜、万能电子试验机和HVS-5Z/LCD维氏硬度计分析测试了Al-1B变质处理前后Zn-6Al-3Mg合金的凝固组织与力学性能。研究表明:变质剂加入量和变质温度对Zn-6Al-3Mg合金的凝固组织中Al-fcc相、Mg Zn2相和Zn-hcp相以及二元Zn/Al和三元Zn/Al/Mg Zn2共晶体的形态和体积分数有明显影响。当Al-1B加入量为0.3 mass%时,Zn-6Al-3Mg合金的抗拉强度、硬度和伸长率都达到最大值。当变质剂加入量相同时,随着变质温度的升高,Zn-6Al-3Mg合金的抗拉强度和伸长率提高;在450℃变质处理时,Zn-6Al-3Mg合金的硬度最高,550℃变质处理后该合金的硬度最低。     

Mn对Mg-3.2Si合金组织和力学性能的影响

采用Mn对过共晶Mg-3.2Si合金进行变质处理,主要考察了Mn含量对合金中初生Mg2Si相的变质效果及合金力学性能的影响。结果表明,Mn对过共晶Mg-3.2Si合金中的初生Mg2Si相具有良好的变质效果。当Mn含量为2%(质量分数)时,变质效果最佳,此时初生Mg2Si相呈多边形,平均颗粒尺寸仅为32μm,相比未变质合金降低了56.8%。随着Mn含量的增加,合金的力学性能呈先提高后降低的趋势。当Mn含量为2%时,合金表现出最佳的力学性能,其抗拉强度和伸长率分别达到187 MPa和3.2%,相比未变质合金提高了67.0%和166.7%。     

Al-3B变质共晶铝硅合金的显微组织与力学性能

采用Al-3B中间合金对不同温度Al-12.6Si合金熔体进行变质处理。结果表明:当变质温度相同时,随着Al-3B加入量的增加,Al-12.6Si合金中α(Al)相的面积分数呈现先增大后减小的变化趋势,当Al-3B加入量为0.4%(质量分数)时,α(Al)相面积分数达到最大值35.6%。当Al-3B加入量为0.4%时,随着变质温度的升高,Al-12.6Si合金中α(Al)相的面积分数也呈现先增大后减小的变化趋势,当变质温度为700℃时,合金组织中α(Al)相的面积分数最大。与未变质Al-12.6Si合金相比,在700℃时经0.4%Al-3B变质处理后,Al-12.6Si合金的抗拉伸强度和伸长率分别提高12%和64%,变质处理后合金的综合力学性能得到明显提高。     

Bi对Al-40%Mg_2Si复合材料组织和性能的影响

为了研究Bi对Al-40%Mg2Si复合材料显微组织和力学性能的影响。利用原位内生工艺制备Mg2Si质量分数为40%的Al-Mg2Si复合材料,并加入不同量的Bi对其细化变质。试验结果显示,Bi的质量分数由0增加至5%时,初生相Mg2Si的平均晶粒尺寸先减小后变大,而抗拉强度、硬度和伸长率则先提高后减小;当Bi加入量约为3%时,初生相Mg2Si显微组织细化效果最为明显,综合力学性能最好。     

Al-3P变质Al-Si合金的组织与力学性能（英文）

在740℃下采用Al-3P作为变质剂对Al-Si合金进行变质处理。利用光学显微镜、Image Pro Plus 6.0软件、扫描电镜和万能电子试验机研究硅含量(7、8、9、10和11,质量分数,%)及变质剂Al-3P加入量(0、0.1、0.3、0.6、1.0和1.5,质量分数,%)对合金显微组织与拉伸性能的影响。结果表明,当变质剂加入量为0.6%时,随着硅含量的增加,变质Al-Si合金中初晶α(Al)相的面积分数增加较多,这一结果可以通过Al-3P的变质引起非平衡共晶点的变化来解释。当合金中硅含量一定(Al-10Si)时,随着变质剂加入量的增加,Al-10Si合金中初晶α(Al)相面积分数先增加后减少。当添加0.6%Al-3P中间合金时,初晶α(Al)相的面积分数达到最大值。与未变质的Al-10Si合金相比,当加入0.6%Al-3P中间合金进行变质处理后,合金的抗拉强度和伸长率分别提高了2.3%和47.0%,拉伸断口呈现出明显的韧性断裂特征。     

超声处理协同Er和Ce复合变质对Mg-3.2Si合金组织及性能的影响

研究了超声处理协同稀土元素Er和Ce复合变质对过共晶Mg-3.2Si合金中组织和力学性能的影响,并探讨了其作用机理。结果表明,在过共晶Mg-3.2Si合金中,添加约0.6%(质量分数,下同)的Er时,初生Mg2Si相的尺寸由150μm减小到40μm,其形态从粗大树枝状变为不规则多面体形状;继续添加1.0%的Ce,可获得5～10μm的多面体或球状初生Mg2Si相,变质效果明显。在此基础上,超声处理可以有效改变初生Mg2Si相的形状和尺寸。当超声功率为1 200W时,可获得颗粒状的初生Mg2Si相,细化效果最佳,合金试样的抗拉强度与伸长率分别达到158MPa和4.5%。对其断口分析可知,经超声处理的合金断裂形式为解理断裂和韧窝的混合断裂形式。     

纳米SiC颗粒对Mg9Al-1Si合金组织及力学性能的影响

研究了纳米Si C颗粒对Mg9Al-1%Si(以下记作Mg9Al-1Si)合金显微组织和力学性能的影响。研究结果表明:Mg9Al-1Si合金组织由α-Mg基体、网状β-Mg17Al12相及粗大汉字状或细长鱼骨状两种形态的Mg2Si相组成。加入质量分数为1%的纳米Si C颗粒,Mg9Al-1Si合金的α-Mg基体晶粒明显细化;β-Mg17Al12相变细变小,网状分布改善不大;粗大汉字状Mg2Si相消失,鱼骨状的Mg2Si相变得更加细小。合金的力学性能得到显著提高,屈服强度提高了13.5%;抗拉强度提高了54%;伸长率由0.48%提高到1.56%,提高了225%.     

Mg-12Al-12Zn-2Si-0.5Ca-xSb合金的组织与力学性能

研究了Mg-12Al-12Zn-2Si-0.5Ca-xSb(x=0.2,0.4,0.6,0.8和1.0,质量分数,%)合金的显微组织与力学性能,重点讨论了Sb对Mg2Si颗粒的细化效果与细化机制。结果表明,在合金中加入微量Sb,形成的Mg3Sb2相作为异质形核核心,细化了Mg2Si相颗粒。随Sb含量从0.2%增加到1.0%,Mg2Si颗粒由粗大的骨骼状和花瓣状逐渐转变为相对细小的多边形状。当Sb含量为0.8%时,Mg2Si颗粒最大尺寸由原来的50μm减小至8μm。此时,合金抗拉强度、屈服强度和伸长率分别达到175.8MPa、167.6MPa和1.67%。合金室温拉伸断裂形式为准解理脆性断裂。     

Gd对Mg-5Si合金组织和力学性能的影响

采用Mg-30Gd中间合金对过共晶Mg-5Si合金进行变质处理,考察了Gd对合金组织与力学性能的影响,并讨论了其变质机理。结果表明,Gd对过共晶Mg-5Si合金中初生Mg2Si相具有良好的变质作用。当加入2.0%的Mg-30Gd时,变质效果最佳,初生Mg2Si相的平均尺寸减小到25μm以下,其形态大部分为近球状,并且分布均匀,合金的抗拉强度和伸长率也达到了最大值,分别为105 MPa和3.1%。但是,当Mg-30Gd增加到3.0%时,初生Mg2Si相又转变为粗大的树枝晶形态。变质机理与稀土元素富集于初生Mg2Si相生长表面抑制优先生长晶向的生长,以及金属间化合物GdxSiy为初生Mg2Si相生长提供了异质形核核心有关。     

锑含量对Mg-6Al-6Si合金组织性能的影响

Mg-Al-Si系合金（AS系列）在凝固过程中容易形成粗大Mg2Si相,严重影响材料的性能。通过添加Sb使Mg2Si尺寸和形状得到改善,以提高材料的性能。结果表明,加入Sb后合金的铸态组织得到明显改变,随Sb加入量的增加初晶Mg2Si逐渐消失,树枝状Mg2Si变得更加细小、弥散,当Sb含量为1.0%时,初晶Mg2Si已完全消失,此时合金的抗拉强度达到最大值。     

不同合金元素对Mg15Al高铝镁合金组织与性能的影响

研究了不同合金元素（Zn,Nd,Si）对Mg15Al镁合金的组织和性能的影响。通过对Mg15Al,Mg15Al1Zn,Mg15Al1Si,Mg15Al1．5Nd四种合金微观组织的观察和力学性能的测定,发现添加了合金元素后Mg合金组织中α—Mg基体和β—Mg17Al12相都得到了不同程度的细化,其中Mg15Al1Si,Mg15Al1．5Nd合金组织中有第三相生成,其形态分别为汉字状、块状,长针状。试验结果表明：添加zn和Nd元素后,抗拉强度比Mg15Al合金显著提高。提高幅度分另4为：13．2％和16．6％,而添加si元素后Mg15Al1Si合金抗拉强度比Mg15Al合金低。添加Nd元素后,伸长率比Mgl5Al合金显著提高,增幅为140％,添加了Si元素和Zn元素后,伸长率比Mg15Al合金低。     

超声处理对原位Mg2Si/AM60复合材料的影响

采用连续功率超声对原位Mg2Si/AM60复合材料熔体进行处理,研究了超声处理对复合材料中的第二相形貌以及力学性能的影响。结果表明,经过600W超声处理60s,原位自生Mg2Si颗粒增强AM60复合材料中的半连续网状Mg17Al12转变成颗粒状,粗大的汉字状Mg2Si破碎成细小的颗粒状,较均匀地弥散分布,晶粒尺寸减少到80μm,其抗拉强度和伸长率较无超声的178.24MPa、3.56%分别提高了10.4%、48.3%,达到196.75MPa、5.28%。     

往复挤压对Mg-6%Si合金组织与力学性能的影响

研究了往复挤压对铸造Mg-6%Si (质量分数,下同)合金微观组织和力学性能的影响。结果表明：往复挤压4道次后,Mg-6%Si合金的显微组织得到显著细化,粗大树枝状的初生Mg2Si相变为细小颗粒状,而汉字状的共晶Mg2Si相也变为弥散分布的点状相,且这些颗粒状的Mg2Si相均匀分布在基体中。往复挤压4道次后,Mg-6%Si合金的抗拉强度和延伸率分别提高了82.3%和810.9%。断口分析表明,往复挤压合金的断裂模式由脆性断裂转变为韧-脆性断裂。     

Effects of silicocalcium on microstructure and properties of Mg-6Al-0.5Mn alloy

1 Introduction Magnesium alloys are attractive for applications in the automobile, aerospace and electronic industries due to their light mass, high stiffness, high specific strength, good dimensional stability and damping capacity. It is the lightest sp…     

RECIPROCATING EXTRUSION OF IN SITU Mg_2Si REINFORCED Mg-Al BASED COMPOSITE

M92Si reinforced Mg-Al based composite with high amount o/silicon was prepared by permanent mould casting, and then extruded by reciprocating extrusion （RE） after the composite was processed by homogenization heat treatment. The effect of RE processing on the morphology and size of M92Si and the mechanical properties of the com- posite were investigated, to develop new ways to refine the M928i phase and improve its shape. The result showed that RE was very useful in refining the M92Si phase. The more the RE processing passes, the better the refining effect would be. Moreover, the uniform distribution of M928i phases would be more in the composite. After the composite was processed by RE for 12 passes, most M92Si phases were equiaxed, with granular diameter below 20 μm, and distributed uniformly in the matrix of the composite. The mechanical properties of the composite could be increased prominently by RE processing, and were much higher than that in the as-cast state. As the temperature rises, the tensile strength is reduced. For the composite RE processed for 12 passes, the tensile strength, yield strength, and elongation are 325.9 MPa, 211.4 MPa, and 3.3% at room temperature, whereas, 288.2 MPa, ,207.7 MPa, and 7.8%, respectively, at 150℃. In comparison with the properties at room temperature, the tensile strength and yield strength are high and only decrease by 11.6% and 1.8% at 150℃. The M928i reinforced Mg-Al based composite possesses good heat resistance at 150℃. The excellent resistance to effect of heat is attributed to the high melting tempera- ture and good thermal stability of fine Mg2Si phases, which are distributed uniformly in the composite, and effectively hinder the grain boundary gliding and dislocation movement.     

脉冲磁场与变质处理对20Mg2Si/Al复合材料中初生Mg2Si相的影响

对比研究了未处理、脉冲磁场处理及脉冲磁场-变质剂复合处理对20Mg2Si/Al复合材料中初生Mg2Si相形貌和分布的影响,同时研究了复合处理条件下,不同磁场电压和频率对初生Mg2Si相的影响。结果表明,磁场处理和复合处理条件下,Mg2Si相尺寸均有所减小;试样从心部到边部,Mg2Si相体积分数逐渐增加,呈梯度分布,但复合处理后,Mg2Si相的梯度分布效果减弱。当磁场电压在0~300V范围内或磁场频率在1~10Hz范围内,随着磁场电压或频率增加,Mg2Si相的尺寸均先增加后减小,转折点分别为200V和5Hz,其梯度分布效果总体上逐渐减弱。试样耐磨性和硬度的变化规律与Mg2Si相的体积分数基本保持一致。     

RECIPROCATING EXTRUSION OF IN SITU Mg2Si REINFORCED Mg-A1 BASED COMPOSITE

Mg2Si reinforced Mg-Al based composite with high amount of silicon was prepared by permanent mould casting, and then extruded by reciprocating extension (RE) after the composite was processed by homogenization heat treatment. The effect of RE processing on the morphology and size of Mg2Si and the mechanical properties of the composite were investigated, to develop new ways to refine the Mg2Si phase and improve its shape. The result showed that RE was very useful in refining the Mg2Si phase.The more the RE processing passes, the better the refining effect would be. Moreover,the uniform distribution of Mg2Si phases would be more in the composite. After the composite was processed by RE for 12 passes, most Mg2Si phases were equiaxed, with granular diameter below 20 μm, and distributed uniformly in the matrix of the composite. The mechanical properties of the composite could be increased prominently by RE processing, and were much higher than that in the as-cast state. As the temperature rises, the tensile strength is reduced. For the composite RE processed for 12 passes, the tensile strength, yield strength, and elongation are 325.9 MPa, 211.4 MPa,and 3.3% at room temperature, whereas, 288.2 MPa, 207.7 MPa, and 7.8%, respectively, at 150° C. In comparison with the properties at room temperature, the tensile strength and yield strength are high and only decrease by 11.6% and 1.8% at 150°C. The Mg2Si reinforced Mg-Al based composite possesses good heat resistance at 150° C. The excellent resistance to effect of heat is attributed to the high melting temperature and good thermal stability of fine Mg2Si phases, which are distributed uniformly in the composite, and effectively hinder the grain boundary gliding and dislocation movement.     

Effect of Si addition on microstructure and mechanical properties of Al-Mg-Si-Zn alloy

The effect of Si addition on the microstructure and mechanical properties of Al-Mg-Si-Zn aluminum alloys were investigated.Results show that the microstructure of Al-Mg-Si-Zn alloy with low Si contents is mainly composed of Mg2Si and Mg5Si6 phases.With the increasing of Si content,Si and Al3.21Si0.47 phases precipitate in the form of eutectic phases in the alloys,at the same time,the mean shape factor of the second phase firstly increases and then decreases.Regression analysis results show that the Si content has the main influence and the mean shape factor has the least influence on tensile strength.Tensile strength increases significantly with the addition of Si,however,there is a remarkable drop in the elongation of the alloys.Decreased elongation is related to the formation of monotonous Al(200)structure and the enlargement of interplanar spacing of(111)and(200)crystalline planes.     

复合添加Si、Nd元素对Mg-11Li-3Al合金组织与力学性能的影响

利用磁悬浮真空高频感应加热法熔炼高质量的镁锂合金,通过Si、Nd元素复合添加来研究其对Mg-11Li-3Al合金组织与力学性能的影响。结果表明:加入Si、Nd元素后,组织中主要生成Mg_2Si和Al_(11_Nd_3 2种第二相,其中Si的添加能够促使合金组织中形成篆体形貌的黑色析出物聚集区,而Nd的加入能够细化这种黑色棒状的析出物,并减小晶粒尺寸、洁净组织。当Nd的添加量为1%(质量分数)时其晶粒细化的效果最佳。经过XRD和EDS分析发现,这种黑色棒状的析出物为Mg_2Si相和Al_(11)Nd_3相的结合体。铸态合金的抗拉强度随着Si含量的增加递增,最后趋于稳定;其塑性并不会随某一种或是复合元素的添加而单调变化。实验得到了一种综合力学性能最佳的合金Mg-11Li-3Al-1Si-1Nd,其抗拉强度和伸长率分别为212.3 MPa和46.2%。