Sn对易切削Bi黄铜组织及性能的影响

用PHILIPS-XL30型扫描电子显微镜(SEM)观察了不同Sn含量对易切削Bi黄铜组织的影响,采用HY-1080型电子拉伸试验机测试了试样的力学性能,使用C6136卧式普通机床检测合金切削性能.结果表明,Sn能改变Bi的分布状态,使Bi从相界向α相迁移,从而有效改善材料性能;但Sn的含量超过2.0%时,合金中生成CuZnSn脆性电子化合物,使材料力学性能指标降低;合金的切削性能随着Sn含量的增加而提高.     

稀土La、Nd对BiSbSn高温钎料力学性能的影响

通过在Bi5Sb8Sn焊料中添加微量稀土La、Nd来提高其力学性能,以获得新型的无铅高温钎料.研究表明:加入稀土(La、Nd)元素可以明显提高Bi5Sb8Sn钎料的力学性能;当稀土(La+Nd)含量小于0.2％时,随着稀土元素的增加,钎料的抗拉强度、剪切强度、伸长率增大;当稀土含量大于0.2％时,随着稀土元素的增加,钎料的抗拉强度、剪切强度、伸长率下降.因此稀土的含量为0.2％时,Bi5Sb8Sn钎料的力学性能最佳.     

元素Bi及稀土La、Nd对Zn-10Al-5Cu钎料性能的影响

研究了Bi及稀土添加对Zn-10Al-5Cu(mass%)基体合金的润湿性能、显微组织、力学性能的影响。结果表明:钎料合金铺展面积随Bi添加量的增加而增大;铜铝接头抗剪强度随Bi添加量的增加而先增加后降低,得到的Zn-10Al-5Cu-2Bi(mass%)是性能较为优良的钎料。在Zn-10Al-5Cu-2Bi(mass%)钎料中添加稀土La、Nd,钎料的润湿性得到改善,当稀土元素添加量为0.15%时,钎料的润湿性能最佳。随着稀土元素的添加,钎料中大块的黑色共析组织逐渐变小,基体组织得到细化;当稀土元素含量为0.1%时,基体组织最为均匀、细密,晶粒也达到最大程度的细化,铜铝钎焊接头的抗剪强度达到最大。因此稀土La、Nd元素在Zn-10Al-5Cu-2Bi(mass%)中的最佳添加量为0.1%左右。     

Bi元素对SAC305钎料合金组织和性能的影响

利用金相显微镜和微型拉伸试验机对SAC305-Bi钎料合金的润湿性、组织和力学性能进行了研究。结果表明:SAC305-Bi钎料合金的润湿性随着Bi元素含量的提高而逐渐提高;当Bi元素含量低于0.5wt%时钎料合金的组织几乎不变化,当Bi元素的含量高于0.5wt%时钎料合金的组织粗化,当Bi元素的含量达到4wt%时形成了一种新的共晶相;SAC305-Bi的抗拉强度随着Bi元素含量的提高而逐渐提高,其延伸长度则逐渐降低。     

Bi含量对SnAgBi无铅焊料润湿性及接头强度的影响

以Sn-3.5%Ag-x Bi(x=0wt%、2wt%、3.5wt%、5wt%和7 wt%)为研究对象,通过润湿性试验和剪切试验探索了Bi含量对焊料润湿性和接头剪切强度的影响。结果表明,随着Bi含量的增大,Sn-3.5%Ag-x Bi焊料润湿角减小,润湿性能得到一定的提高。随着Bi含量的增加,钎焊接头剪切强度先是增大,然后减小,Bi含量为5%时剪切强度最大;当Bi含量从0增加到5%时,接头剪切强度明显增加。     

微量稀土镧钕对Bi5Sb8Sn力学性能影响

通过在Bi5Sb8Sn基体钎料上添加微量稀土镧钕形成Bi5Sb8SnRE新型钎料合金,研究了稀土镧钕对钎料合金力学性能的影响,同时对显微组织进行了分析.结果表明,稀土镧钕含量为0.2%时,Bi5Sb8SnRE合金抗拉强度和抗剪强度达到最大值,分别为58.30 MPa和15.50 MPa,合金抗拉强度和钎焊接头的抗剪强度较基体钎料Bi5Sb8Sn分别提高了44.2%和57.0%.显微组织分析表明,微量稀土镧钕的添加能显著细化该钎料的合金组织,改善合金的组织分布,提高钎料的力学性能;但当稀土含量超过0.2%时,稀土化合物的数量增多,钎料的力学性能下降.     

稀土元素Er对Bi5Sb8Sn钎料力学性能的影响

通过向Bi5Sb8Sn钎料合金中添加适量的稀土元素铒(Er),研究了不同含量的稀土Er对Bi5Sb8Sn无铅钎料合金力学性能的影响。结果表明,微量稀土Er的添加能显著细化该钎料组织,改善合金的组织分布情况,提高钎料的力学性能;稀土w(Er)0.5%时,Bi5Sb8SnRE合金抗拉强度和钎焊接头的抗剪强度较基体钎料Bi5Sb8Sn分别提高了41.8%和83.0%.;但当稀土w(Er)0.5%时,则组织粗化,钎料力学性能下降。     

稀土对B级钢组织和低温韧性的影响

研究不同稀土含量对摇枕、侧架用B级钢组织和低温韧性的影响,并在相同的热处理条件下,与不加稀土的实验钢进行对比。结果表明,稀土可以细化钢组织,在稀土含量低于0.3%时,随着稀土含量增加,实验钢组织细化效果增强,当稀土含量高于0.3%时,细化组织效果减弱,组织不均匀性增强;随着稀土含量增加,实验钢中夹杂物形态改善、数量明显减少;与未加入稀土实验钢相比,加入稀土后实验钢-60℃冲击吸收功提高,当稀土含量不高于0.3%时,随着稀土含量增加,-60℃冲击吸收功增加,当稀土含量高于0.3%时,-60℃冲击吸收功降低。     

Bi对Sn-Cu-Zn无铅钎料性能的影响

以Sn-0.7Cu-Zn三元合金钎料为基础,研究添加不同含量的Bi元素对合金的熔点、电导率、润湿性以及力学性能的影响。通过差式扫描量热仪(DSC)、万能拉力试验机分别对不同配比的钎料合金进行熔点和力学性能测试,采用铺展性试验法表征其在铜铝板上的润湿性能。研究表明:随着Bi元素含量的增加,其熔点开始下降,但熔程会增加;电导率随着Bi元素含量的增加而减少。随着Bi元素含量的增加,四元合金钎料润湿性能先增加后减少,Bi的含量为1%时可以大幅提高铜铝板上的润湿性能。Bi元素能影响合金的抗拉强度,但合金的伸长率会下降。     

Cu含量对Bi5Sb钎料润湿性能和力学性能的影响

通过在Bi5Sb中添加不同含量的Cu形成新型BiSbCu三元合金.结果表明:在Bi5Sb钎料合金中添加0.5%～5.0%(质量分数)Cu,BiSbCu钎料合金的熔点变化不大,但其润湿性能和力学性能明显改善;当Cu含量为1.5%时,(Bi5Sb)1.5Cu钎料合金的润湿性能和力学性能最好,与基体Bi5Sb相比,(Bi5Sb)1.5Cu的铺展面积增大57.8%,抗拉强度提高212.4%;随着Cu含量的增大,针状组织Cu2Sb的含量逐渐增多,钎料合金性能下降.     

铋黄铜组织及性能的研究

与铅黄铜相比,铋黄铜对人体和环境无害,可代替铅黄铜用于许多工程领域。日本、德国等国家都开发了铋黄铜,并研究了铋黄铜的切削性能、力学性能和耐蚀性能。近年来,我国也开展了铋黄铜的研究工作,研究了不同含铋量黄铜的显微组织、力学性能、耐脱锌腐蚀性能,特别是切削性能。结果表明,铋黄铜的组织主要为α相和β相,铋以单质形式存在于晶界和相界;铋黄铜的切削性能与铅黄铜相近;铋能明显改善黄铜的耐脱锌腐蚀性能。目前,铋黄铜的某些性能尚未完全达到铅黄铜的水平,价格也较昂贵,有待进一步研究。     

无铅易切削铜合金

根据金属材料的切削机理和铜合金的基本性质,阐述无铅易切削铜合金成分选择的基本思路,提出以弥散分布的金属间化合物代替易切削铅黄铜中的铅或无铅铋黄铜中的铋,从而实现易切削黄铜的无铅化。详细介绍国外无铅易切削铋黄铜研究开发的一些成果和石墨/铜合金复合材料的研究情况,总结国内无铅易切削铜合金的研究情况,结合自己的研究结果,指出无铅易切削铜合金的研究方向是采用适当的元素形成脆而不硬的金属间化合物,并采用一定的加工手段使其呈弥散分布。     

微量In对AgCuZn钎料组织和性能的影响

研究了不同In含量银钎料的熔化温度、铺展性能、钎料显微组织以及钎缝力学性能的变化规律.以紫铜、黄铜为母材,采用火焰钎焊方法,用对接和搭接接头形式进行钎焊试验.结果表明,在银钎料中添加微量In元素,能够降低钎料的熔化温度,改善钎料的铺展性能,并显著改变钎料显微组织.对于黄铜对接来说,钎焊接头的抗拉强度,随银钎料中In含量的增加而呈抛物线方式增加;除黄铜对接接头外,其它形式的接头断裂位置均在母材上,说明含In银钎料的力学性能优良.     

Microstructure and properties of cutting magnesium-brass containing no lead

1 INTRODUCTIONLead-brass has excellent cutting ability , me-chanical and physical properties and is one of themost widely used copper alloys . The occupationratio of brass tube to all kinds of tubes reaches90 % in developed countries . The cutting lead-brass is a dual-phase brass and fine lead particlesdistribute dispersivelyin grains and on grain boun-ries . Theleadin wasted brass can easily beleachedand dissolvedinto soil .If the wasted lead-brass isburned in air ,the lead will become p…     

易切削黄铜的研究现状及其机理浅析

传统的易切削铅黄铜中含有的铅元素对环境和人都有极大的危害,所以急需寻找一种或者多种元素来替代易切削铅黄铜中的铅.本文介绍了易切削黄铜的发展现状,并经过对比分析其性能了解几种有发展前景的易切削黄铜.从易切削黄铜的切削特点出发研究其易切削的本质,并通过添加微量元素如Ni、P、Ca等,以及稀土元素Ce来改善黄铜的切削性能,达到易切削黄铜低铅或者无铅的目的.     

无铅磷钙黄铜的组织与性能

通过熔铸方法,于中频感应炉中制备无铅磷钙黄铜铸锭,利用扫描电镜、电子能谱仪、电子万能试验机及卧式车床等手段,研究磷钙黄铜合金的显微组织和力学、切削及耐脱锌腐蚀性能,并结合切屑的形貌观察,分析金属间化合物对切削性能的改善作用。结果表明:磷、钙显著改变了黄铜的组织与性能,使得磷钙黄铜的组织由α相、β相和分布在晶界上及晶粒内的金属间化合物颗粒组成;无铅磷钙黄铜合金的主要成分(质量分数)为57%~60%Cu、40%Zn、0.7%P、0.5%Ca时,合金显示出优良的综合性能,其抗拉强度为362.7 MPa,伸长率为15.0%,布氏硬度为105.0HB,耐脱锌腐蚀深度为321.9μm,切削性能与铅黄铜HPb59-1相当。     

Effects of Ga and In on the properties of cadmium-free Ag-Cu-Zn filler metal

Melting temperature,spreadability,mechanical properties and the microstructures of joints brazed with silver-base filler metals including different amounts of Ga and/or In were studied respectively in this paper,and the results show that the melting temperature of the silver-base filler metals is decreased,spreadability of the silver-base filler metals is improved,and the microstructures of silver-base filler metals are refined obviously with the addition of Ga and/or In.Using copper and brass plates as base metal and brazing with flame method,the mechanical properties of the lap-joint and butt joint were also examined and analyzed respectively,and the results indicate that the fracture position of two kinds of brazed joints occurred on the base metal,except for the lap-joint of brass,which shows better mechanical properties of the joints brazed with the silver-based filler metals including Ga.For the lap-joint of brass,the tensile strength gradually increased with the increase of Ga content,while the addition of In has little effect on mechanical properties.It is also found that the best comprehensive properties of cadmium-free Ag-Cu-Zn filler metals are obtained when Ga content is about 3.0 wt.% and In content is between 1.5 wt.% and 2.0 wt.%.     

铅黄铜HPb59-1连续切削的颤振及其特征研究

试验研究了铅黄铜HPb59-1材料在连续切削加工时产生的切削颤振,得到了切屑形成频率与切削用量之间的关系,以及切削颤振形成频率和振幅。试验结果表明,铅黄铜HPb59-1材料因切削加工过程中周期性地产生剪裂型切屑而产生切削颤振。并由此总结得到铅黄铜HPb59-1材料加工产生的切削颤振所具有的一般性特征。     

Physico-chemical properties of PbO2-anodes modified by Bi3+ ions

Physico-chemical properties of PbO₂-anodes modified by bismuth have been investigated in this work. The incorporation of Bi³⁺ dopant in the deposition solution allows one to obtain modified lead dioxide materials, bismuth content in which growths as increases its concentration in the solution. It was established that current density 10 mAcm^?2 and (10 ± 1)°C are optimal conditions for the deposition of lead dioxide modified by bismuth. In this case deposits appear shiny dark grey, with 1 mm thickness and good adhesion to the substrate. Resulting materials have had compact structure with spindle-shaped submicron and nanosized crystals. The increasing of the bismuth content in the deposit leads to the oxygen overpotential growth and enhancing of the oxidation rate of p-nitroaniline due to increase of the bond strength of chemisorbed oxygencontaining particles with the electrode surface.     

Effect of post-weld heat treatment on joint properties of friction welded joint between brass and low carbon steel

Abstract

This paper describes the effect of post-weld heat treatment (PWHT) on joint properties of copper–zinc alloy (brass) and low carbon steel friction welded joints. The as-welded joint obtained 100% joint efficiency and the brass base metal fracture without cracking at the weld interface, and had no intermetallic compound layer. The joint efficiency with PWHT decreased with increasing heating temperature and its holding time, and its scatter increased with those increasing parameters. When the joint was heat treated at 823 K for 360 ks, it did not achieve 100% joint efficiency and fractured between the weld interface and the brass base metal although it had no intermetallic compound. The cracking at the peripheral portion of the weld interface was generated through PWHT. The cracking was due to the dezincification and the embrittlement of the brass side during PWHT.