Interfacial microstructure and properties of YG11C/42CrMo joint brazed with BCu64MnNi filler metal

Brazing hard alloy to high strength steel, incomplete atomic diffusion and excessive brittle reaction product precipitation at the faying interface are usually suffered because of incomplete understanding the process of the initial interface disappearing and diffusion layer forming and evolving. In this paper, hard alloy YG11C (WC-11wt.%Co) and high strength steel 42CrMo were picked up as base metals and BCu64MnNi as filler metal to clarify the interfacial microstructure evolution. The process parameters of dwell time were set as 30s, 60s, 120s, and 300s and braze temperature were set as 950℃, 970℃, 990℃, 1010℃, the effect of which on the evolution of interfacial microstructure, tensile strength, integrated with fracture morphology analysis, were conducted. The results showed that increasing brazing temperature from 950℃ to 970℃, no significant difference existed in the joint interface, whereas brazed at 990℃, the binder phase erosion occurred, i.e. the liquid filler metal etched into Co binder phase of WC-Co base metal, which caused WC particles debonding from the base metal surface and formed an micro-anisotropic zone.. Increase temperature to 1010℃, severe binder erosion happened so as to micropores appear. Through the parameters optimization, the tensile strength can reach to the maximum 589MPa at temperature of 970℃. The dwell time showed similar effect on tensile strength because longer dwell time also caused erosion and porosity owing to long-time diffusion and reaction.     

硅丙乳液防水涂料及其在不同基材上的应用研究

硅丙乳液是纳米二氧化硅和丙烯酸酯通过钛螯合交联共聚制成的有机无机复合乳液,本文简述了其制备机理和特性,并以瓷砖外墙、无釉仿古瓦屋面和金属屋面的渗水修复为例,详细介绍了硅丙乳液及由其配制的防水涂料的施工工艺。     

铜-钢扩散焊接头钢侧晶间渗透现象的探讨

基于材料物理、相平衡等领域的晶界相转变概念,借助瞬间液相扩散焊手段,以铜与不锈钢异种材料为研究对象,对铜-钢扩散焊接头中合金液相沿钢侧晶界的渗透现象进行初步探讨.结果表明,试验温度范围内,添加单质中间层时,钢侧结合界面均较平直;添加QSn6.5-0.1+Au复合中间层时,钢侧母材存在液相合金的晶间渗透现象,950℃高温...     

铜-不锈钢真空扩散连接工艺及界面微观结构

采用电镀工艺,在纯铜基体表面制备出约2.74μm的单质Au镀层,在950℃,1MPa压力下实现了铜与不锈钢的真空扩散接合,并与铜-钢直接连接接头进行界面显微结构对比.试验结果表明:在直接连接800℃时结合界面钢侧存在明显的元素沿晶界扩散现象,接头抗剪强度158MPa,约为铜母材强度的86%;添加单质Au镀层中间层时,有...     

镁合金与钛合金的瞬间液相扩散焊

为实现镁合金AZ31B与钛合金Ti6A14V的可靠连接，研究了两者以Al为中间层的瞬间液相扩散焊接头的微观结构与连接强度。研究结果表明：当焊接时间为180min时，焊接温度是影响界面反应热力学与动力学的主要参数，其对接头的微观组织、接头界面新生相构成与连接强度有重要影响。保温温度低于450℃时，AZ3IB／AI界面无液相产生，无法实现AZ31B与Ti6A14V的可靠连接；保温温度在450℃～480℃变化时，温度对AZ31B／Al／Ti6A14V界面反应的动力学因素有明显影响，且直接决定了焊后接头新生相的构成与分布。470℃保温180min的接头剪切强度较高（72．4MPa），达到AZ31B母材（86MPa）的84．2％。     

聚对苯二甲酰对苯二胺锂离子电池隔膜材料研究进展

锂离子电池已经得到广泛应用,但是其隔膜安全性一直没有得到彻底解决。液晶高分子聚对苯二甲酰对苯二胺(PPTA)具有优异的耐热、耐腐蚀、制品尺寸稳定性好等特点,其纤维材料对位芳纶具有优异的力学性能,因此PPTA作为锂离子电池隔膜材料具有很好的应用前景。但是将PPTA制备成多孔膜是一个巨大的技术挑战。本文从技术进展的角度,详细综述了锂离子电池隔膜制备技术的进展情况,对PPTA电池隔膜的各个技术路线进行比较分析。最后对本研究团队在PPTA锂离子电池隔膜领域所做工作进行简要介绍。结果表明,利用PPTA纳米纤维制备技术可以制备出厚度、孔隙率及电池性能优异的锂离子电池隔膜,PPTA隔膜具有很好的应用前景。     

多功能等离子弧装置

研制一种新型多功能等离子弧装置，它具有等离子弧焊接、切割、喷涂和喷焊四种功能。为了提高工艺过程的稳定性，并实现多功能集成一体化，设计中采用了先进的晶闸管整流技术和可编程序控制器ＰＣ机控制技术。实践表明，该装置具有线路简单、控制灵活、故障率低和维修方便等特点。     

基于DSP的软开关点焊逆变电源控制系统硬件设计

提出了以TNS320LF2407为基础的软开关点焊逆变电源智能控制系统的设计方法，着重阐述了硬件电路的设计原则、思想以及器件选型，并进行了联机调试。可以实现对4路IGBT管的PWM驱动信号的时序控制，软、硬件设计满足IGBT软开关功能，具有良好的系统自调整功能。     

暖气片水箱纵缝自动焊接设备的电气控制

详细介绍了暖气片水箱纵缝自动焊接设备电气控制系统的设计思想、工作原理．并给出了具体的控制电路。生产实践表明，该电气控制系统工作稳定、可靠，完全满足暖气片水箱纵缝的焊接生产要求。     

Friction welding of TiAl intermetallics and structural steel by applying Inconel 718 as interlayer

0IntroductionInterlayer metal is usually introduced while solidwelding heterogeneous metals with different chemical com-ponents and microstructures[1-3].The diffusion activationenergy(DAE)in both sides of interlayer and base metalcould be affected by the …