时效对Sn、Bi微合金化的新型无铅易切削AI—Mg—Si合金的组织与性能影响

采用力学性能测试、X射线衍射物相分析、SEM观察研究了时效对固溶-冷拉处理后的Sn、Bi微合金化的新型无铅易切削6xxx系Al-Mg—Si合金棒材微观组织和力学性能影响，并比较了该合金与6262合金的切削性能。结果表明：其最佳的时效热处理工艺为170℃／10h，在此工艺磐件下，抗拉强度为348MPa，屈服强度为339MPa，延伸率为12．5％。峰时效态合金的物相组成为Al基体，主要强化相Mg2Si，低熔点物质Mg2Sn、Mg3Bi2和Bi及少量的CuAl2相。切削性能试验表明，用Sn和Bi微合金化6xxxAl-Mg—Si合金的切削性能比Pb和Bi微合金化的传统6262合金稍好。     

Sn和Bi微合金化的无铅易切削6xxx铝合金的微观组织结构与性能

采用力学性能测试、X射线衍射物相分析、SEM背散射扫描和能谱分析、透射电镜分析技术和金相实验技术研究了时效工艺对固溶-冷拉处理的用Sn和Bi微合金化的无铅易切削6xxx系Al—Mg—Si合金棒材显微组织结构特征和力学性能的影响。结果表明：其最佳的时效热处理工艺为170℃／6h,在此工艺条件下,抗拉强度为314Mpa,屈服强度为286Mpa,延伸率为12．8％。合金的物相组成为Al基体,主要强化相Mg2Si,低熔点物质Mg2Sn和Sn以及Mg3Bi2和Bi以及少量的Al0．56Mr0．44。切削性能试验表明,用Sn和Bi微合金化6xxx合金的切削性能与Sn微合金化而不含Bi的6020合金以及用Pb和Bi微合金化的传统6262合金相当。     

时效对Sn、Bi微合金化的新型无铅易切削Al-Mg-Si合金的组织与性能影响

采用力学性能测试、X射线衍射物相分析、SEM观察研究了时效对固溶-冷拉处理后的Sn、Bi微合金化的新型无铅易切削6xxx系Al-Mg-Si合金棒材微观组织和力学性能影响,并比较了该合金与6262合金的切削性能.结果表明:其最佳的时效热处理工艺为170 ℃/10 h,在此工艺条件下,抗拉强度为348 MPa,屈服强度为339 MPa,延伸率为12.5%.峰时效态合金的物相组成为Al基体,主要强化相Mg2Si,低熔点物质Mg2Sn、Mg3Bi2和Bi及少量的CuAl2相.切削性能试验表明,用Sn和Bi微合金化6xxxAl-Mg-Si合金的切削性能比Pb和Bi微合金化的传统6262合金稍好.     

全谱直读ICP-AES法测定金属铜及其合金中的多种元素

采用全谱直读ICP-AES法直接测定有色金属铜及其合金中Cr、Ni、Mn、P、Si、Al、Fe、Pb、Sn、As、Sb、Bi、Mg、Zr、Zn 15种元素,优选了仪器测定参数和分析谱线,研究了基体效应、共存元素间干扰及干扰校正方法.     

Mg对再生铅黄铜C3604合金组织及性能影响

文章针对废杂黄铜直接重熔制备铅黄铜C3604合金,精炼时采用金属镁对合金熔体进行变质处理,研究了金属镁对再生铅黄铜C3604合金组织及性能影响。结果表明,废杂铜重熔制备C3604合金熔体中,Mg元素与Sn、Si、Fe及Al等杂质元素结合,形成Mg2Sn相及富含Sn、Pb、Mg、Si和Al元素的多元素聚集颗粒相;Mg元素还与Pb元素结合,使Pb颗粒相数量减少,其含量不宜过高而使Pb相数量减少,Mg元素含量为0.28wt%时C3604合金形貌组织理想,且产品切削性能较好。     

Al和Sn对再生Bi黄铜组织和性能的影响

在再生Bi黄铜中分别加入不同含量的Al和Sn,研究Al和Sn元素对再生Bi黄铜合金组织和性能的影响。研究表明:随着Al和Sn含量的增加,铸态下合金晶粒不断减小,热轧态下合金晶粒先增大后减小;Bi由薄膜状转变为颗粒状;Al和Sn的质量分数分别为0.5%和0.8%时合金的力学性能最佳。通过计算表面张力的方法分析Bi形态发生改变和力学性能改善的原因。分析可得:质量分数为0.5%的Al和0.8%的Sn可以增大Bi在合金中的润湿角,从而使薄膜状的Bi减少,颗粒状的Bi增多;薄膜状的Bi能抑制基体的割裂,最终改善合金的力学性能。     

6063铝棒质量提高的措施探讨

6063合金棒属Al—Mg—Si系合金,本文通过介绍Al—Mg—Si系合金的基本特点、合金元素以及熔炼过程中工艺控制,并对其进行探讨分析,提出了6063铝合金棒质量提高的措施。     

ICP-AES法同时分析有色金属铜及其合金中15种元素

采用全谱直读等离子体发射光谱仪,直接测定有色金属铜及其合金中Cr、Ni、Mn、P、Si、Al、Fe、Pb、Sn、As、Sb、Bi、Mg、Zr、Zn15种元素,优选了适宜的仪器测定参数和分析谱线,研究了基体效应、共存元素间干扰及干扰校正方法,通过对实际样品的分析试验,灵敏度、准确度、精密度、回收率均取得令人满意的结果.     

Mg-xSn-2Al-1.5Zn-0.8Si(x=3,5,8)合金的组织和性能

采用光学显微镜(OM),扫描电镜(SEM),能谱仪(EDS),X射线衍射(XRD)分析以及拉伸、全浸腐蚀等实验手段,研究了Mg-x Sn-2Al-1.5Zn-0.8Si(x=3,5,8;%,质量分数,下同)合金铸态下的组织和性能。结果表明:Sn元素与基体Mg生成Mg2Sn相,该相能阻断Mg2Si相的枝晶生长,并对铸态组织具有细化作用;随着Sn含量的增加,细化作用逐渐加强,但同时析出的Mg2Sn相增多,组织的均匀性下降。随着Sn的增加,合金延伸率逐渐减小,而抗拉强度呈现先升高后降低的趋势,过多的Sn对合金力学性能不利,Sn含量在5%时强韧性达到较佳配合;Sn含量为5%的合金耐高温性能较好,Sn含量为3%时耐高温性能较差。合金在腐蚀过程中,多数金属间化合物(Mg2Sn,Mg2(Si,Sn)和Mg2Si等)充当阴极相,Mg基体则充当阳极相,二者构成电偶腐蚀;Sn的加入使合金的耐蚀性能下降,特别是Sn含量超过5%时,耐腐蚀性能下降显著,腐蚀形貌特征从点蚀变为坑蚀。     

Ca和Sr对铸态Mg-Sn-Si合金组织和性能的影响

用X射线衍射仪(XRD)、扫描电镜(SEM)、光学显微镜(OM)研究了铸态Mg-Sn-Si-Ca-Sr合金的相组成和显微组织,用力学性能试验机测定了合金的拉伸性能.结果表明,Mg-5Sn-xSi-0.5Ca-0.5Sr(x=1,2)合金由α-Mg、Mg2Sn、Mg2Si和CaMgSn相所组成,Mg2Si相含量随Si元素的增加而增加.对于Mg-5Sn-1Si-yCa-0.5Sr(y=0.5,2)合金,Ca的质量分数提高到2%后会促进Mg2Ca相和CaMgSn相形成,但同时抑制了Mg2Sn、Mg2Si相的析出,从而导致合金性能下降.对于Mg-5Sn-2Si-0.5Ca-ySr(y=0.5,2)合金,当Sr的质量分数由0.5%提高到2%时,Mg2Si和Mg2Sn相均得到显著细化,并促进了基体内MgSn(Sr,Ca)相形成,从而提高了合金的抗拉强度与屈服强度.     

Effect of Gd on microstructure,mechanical properties and wear behavior of as-cast Mg–5Sn alloy

Effect of minor Gd addition on the microstructure, mechanical properties and wear behavior of as-cast Mg–5Sn-based alloy was investigated by means of OM, XRD, SEM, EDS, a super depth-of-field 3D system, standard high-temperature tensile testing and dry sliding wear testing. Minor Gd addition has strong effect on changing the morphology of the Mg–5Sn binary alloy. Gd addition benefits the grain refinement of the primary α-Mg phase, as well as the formation and homogeneous distribution of the secondary Mg₂Sn phase. The mechanical properties of the Mg–5Sn alloys at ambient and elevated temperatures are significantly enhanced by Gd addition. The wear behavior of the Mg–5Sn alloy is also improved with minor Gd addition. The alloy with 0.8% Gd addition exhibits the best ultimate tensile strength and elongation as well as the optimal wear behavior. Additionally, the worn surface of the Mg–5Sn–Gd becomes smoother in higher Gd-containing alloys. The best wear behavior of alloy was exhibited when Gd addition was up to 0.8%, showing a much smoother worn surface than that of control sample. The improvement of tensile properties is mainly attributed to the refinement of microstructure and the increasing amount and uniform distribution of Mg₂Sn phase. The larger amount of Mg₂Sn phase uniformly distributed at the grain boundary of Mg–Sn–Gd alloys act as a lubrication during sliding, and combined with smaller grain size improve wear behavior of the binary alloy.     

电子部件封装用无铅焊接材料的研究动态

介绍了无铅焊接材料的研究背景，并以发展前景良好的候选材料Sn-Ag，Sn-Bi，Sn-Zn系共晶合金为例，介绍了无铅焊接材料的研究现状和存在的问题。研究表明，Sn-3．5％Ag基合金具有良好的力学性能，但熔点偏高；Sn-58％Bi基合金的机械性能略差，并且熔点太低；Sn-8％Z。基合金虽然有合适的熔点，但润湿性差。本文还简略地介绍了由日本开发的材料设计系统以及在无铅材料开发中的作用，并指出该材料设计系统将是开发无铅焊接材料中不可缺少的工具。     

Crystallization studies of the β (Mg2Pb) phase and its phase boundaries in the Pb-Mg-Bi system

A peritectic reaction between Mg bismuthide and Mg plumbide changes from an even to an odd reaction at 310 °C (0.14 wt pct Bi and 4 wt pct Mg) owing to the incorporation of 1.6 wt pct Bi into Mg plumbide; this value was calculated from material balances of equilibrium studies of this reaction and confirmed by direct analysis of crystals using a “Cameca Microbeam” electroprobe microanalyzer. A model is presented in which an atom of Pb in the unit cell, 46 Mg₂Pb Mg₂Pb₅, is replaced by an atom of Bi which gives a concentration of 1.63 to 1.71 wt pct Bi depending on the actual species of Mg plumbide present. The phase boundary for double saturation with Pb and Mg plumbide, established from the data of equilibrium tests, shows a minimum temperature of 251.8 °C at 0.008 wt pct Bi and 2.2 wt pct Mg. Alloys in the primary Pb phase field adjacent to this boundary show undercooling to less than 248.5 °C followed by one or two sharp temperature increases to 250.5 °C, with the initiation of the removal of Bi when double saturation occurs giving a final liquid phase containing less than 0.001 wt pct Bi. Crystallization paths for alloys in the Mg plumbide phase field show a catatectic reaction and polymorphic transformations in the intermetallic compound. The removal of Bi is dependent on the concentration of Bi and Mg in the initial alloy. In systems containing sufficient Mg, a final alloy containing less than 0.001 wt pct Bi can be produced, and these conditions have been used as the starting point for the development of a process for the removal of Bi from Pb. Finally, the crystallization paths show there is a change in the thermal properties of the liquid alloy at 0.008 wt pct Bi which is independent of the temperature and concentration of Mg, and further work is required to resolve this finding.     

Gallium-induced magnesium enrichment on grain boundary and the gallium effect on degradation of tensile properties of aluminum alloys

By applying a controlled amount of gallium (3 mg or 5 mg) to double-notched samples, the effects of the gallium on the grain boundary chemistry and tensile properties of AA6061-T4 alloy were investigated. Commercial-purity aluminum AA1050 was used for comparison to determine whether alloying elements would correlate with Ga-induced embrittlement and to elucidate the physical reason that governed the occurrence of intergranular fracture in the AA6061 Al-Mg-Si alloy. The AA6061 and AA1050 samples wetted by 3 mg or 5 mg of Ga were held statically for 7 days before tensile tests were conducted. The 6061 Al-Mg-Si samples with gallium were fractured intergranularly. However, the Ga-treated AA1050 samples had a mixed fracture mode, showing better strength and ductility than the Ga-treated AA6061 alloy, independent of whether the samples had their longitudinal axis parallel or perpendicular to the rolling direction, or the holding temperatures before tensile tests. Auger electron spectroscopy scanning the intergranular facets on fracture surfaces showed that the Auger peak-to-peak ratio I_Ga/I_Al of 6061 samples was similar to that of 1050 samples, but the high intensity of Mg signal was detected from the intergranular fracture surface of the AA6061 alloy. Magnesium being induced by Ga to enrich on the grain boundary and free surface of the AA6061 alloy was confirmed. The intergranular embrittlement of the 6061 T4 Al-Mg-Si alloy wetted by small amount of Ga involves the combination of the following two effects: Ga metal on grain boundary embrittlement, and Ga-induced magnesium enrichment on grain boundary that further decreases the strength of the grain boundary.     

A comparative study of the microstructures observed in statically cast and continuously cast Bi-In-Sn ternary eutectic alloy

A ternary eutectic alloy with a composition of 57.2 pct Bi, 24.8 pct In, and 18 pct Sn was continuously cast into wire of 2 mm diameter with casting speeds of 14 and 79 mm min⁻¹ using the Ohno Continuous Casting (OCC) process. The microstructures obtained were compared with those of statically cast specimens. Extensive segregation of massive Bi blocks, Bi complex structures, and tinrich dendrites was found in specimens that were statically cast. Decomposition of γSn by a eutectoid reaction was confirmed based on microstructural evidence. Ternary eutectic alloy with a cooling rate of approximately 1 °C min⁻¹ formed a double binary eutectic. The double binary eutectic consisted of regions of BiIn and decomposed γSn in the form of a dendrite cell structure and regions of Bi and decomposed γSn in the form of a complex-regular cell. The Bi complex-regular cells, which are a ternary eutectic constituent, existed either along the boundaries of the BiIn-decomposed γSn dendrite cells or at the front of elongated dendrite cell structures. In the continuously cast wires, primary Sn dendrites coupled with a small Bi phase were uniformly distributed within the Bi-In alloy matrix. Neither massive Bi phase, Bi complex-regular cells, nor BiIn eutectic dendrite cells were observed, resulting in a more uniform microstructure in contrast to the heavily segregated structures of the statically cast specimens.     

Effect of Sn Alloying on the Diffusion Bonding Behavior of Al-Mg-Si Alloys

Effect of Sn as an alloying element on the diffusion-bonding behavior of Al-Mg-Si alloy has been studied by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical testing of the diffusion-bonded joint. XRD results revealed the formation of Mg₂Sn and (Sn) phases during solidification following induction casting. DSC results showed local liquid (Sn) formation during the bonding process for Sn-containing alloys, where its amount was found to be increasing with the increasing Sn content. Results revealed that Sn addition leads to an increase in the bond shear strength of the diffusion-bonded joints and elimination of the irregularities formed on the bonded interface. Fractured surfaces showed that formation of (Sn) layer at the bonded interface causes the fracture to transform from the ductile to the mixed fracture mode.     

Sr对Mg-5Sn-5Zn铸造镁合金组织的影响

通过光学显微镜、扫描电镜和X射线衍射仪研究了Mg - 5Sn - 5Zn - xSr(x=0,0.5,1,2)4种铸造镁合金的显微组织和相组成.结果表明:在Mg -5Sn -5Zn合金中加入质量分数为0.5％ ～2％的Sr元素后,不但能够缩小α - Mg枝晶间距,而且还能形成三元相MgSnSr.随着Sr含量的增加,在晶界析出的Mg2Sn相减少,晶内的MgSnSr相增加.合金中的MgZn相与Mg2Sn相依附在一起,大多数的MvgZn相以α-Mg+ MgZn相的共晶方式存在.     

Effects of Cu,Bi, and In on microstructure and tensile properties of Sn-Ag-X(Cu,Bi, In) solders

Effects of minor additions of Cu, Bi, and In on microstructure, melting temperature, and tensile properties of Sn-Ag-based lead-free solders were investigated. It was found that the intermetallic compounds (IMCs) Ag₂In and Cu₆Sn₅ are formed in In- and Cu-containing solders, respectively. At low concentration, Bi dissolved in the Sn matrix and tended to precipitate pure Bi particles at the solubility limit of 4 wt pct Bi. The formation of large Ag₃Sn precipitates from the solder matrix was suppressed when alloying bismuth into the Sn-Ag alloy. The Bi addition resulted in a significant linear increase of the ultimate tensile strength (UTS) of solders, which is attributed to a solid-solution hardening mechanism. Solder strengthening due to In and Cu is less pronounced and attributed to a dispersion strengthening mechanism. The additions of Cu, Bi, and In all depressed the melting temperatures of Sn-Ag-based solders; however, In is the most effective one.