Ti-Ni合金对SiCp/Al MMCs等离子弧原位焊接焊缝性能的影响

以Ti-Ni合金作为填加材料,采用氮氩混合等离子气对SiCp/Al基复合材料进行等离子弧原位焊接.结果表明,填加Ti-Ni合金进行等离子弧原位焊接,在焊缝组织中生成了新的增强颗粒TiN,TiC,AIN,Al3Ti和Al3Ni未发现明显的针状相生成,有效的抑制了脆性相Al4C3,并且接头组织致密,结合较好.Ni元素的添加,降低了SiC溶解程度,使得熔池中的结晶热显著提高,改善了熔池的流动性.同时在焊缝组织中形成了新的增强相AlNi,Al3Ni,从而有效地提高接头的力学性能.采用Ti-Ni合金进行等离子弧原位焊接,接头的抗拉强度为215.4MPa,达到母材强度的67.3%.     

Ti-Ni合金对SiCp/AlMMCs等离子弧原位焊接焊缝性能的影响

以Ti-Ni合金作为填加材料,采用氮氩混合等离子气对SiCp／Al基复合材料进行等离子弧原位焊接。结果表明,填加Ti-Ni合金进行等离子弧原位焊接,在焊缝组织中生成了新的增强颗粒TiN,TiC,A1N,Al3Ti和Al3Ni,未发现明显的针状相生成,有效的抑制了脆性相Al4G3并且接头组织致密,结合较好。Ni元素的添加,降低了SiC溶解程度,使得熔池中的结晶热显著提高,改善了熔池的流动性。同时在焊缝组织中形成了新的增强相AlNi,Al3Ni,从而有效地提高接头的力学性能。采用Ti-Ni合金进行等离子弧原位焊接,接头的抗拉强度为215．4MPa,达到母材强度的67．3％。     

Ti-Al-Si-Mg对SiCp/Al基复合材料等离子弧原位焊接焊缝组织和性能的影响

以填充自制药芯铝焊丝的形式向熔池内部直接添加Ti,Al,Si,Mg等金属元素,用氩氮混合等离子气体对SiCp/Al基复合材料进行等离子弧原位焊接.分析了Ti-Al-Si-Mg以及它们的氧化物对焊缝组织和性能的影响.结果表明,以Ti-Al-Si-Mg作为原位反应填充材料,可以有效抑制针状脆生相Al4C3的生成,改善熔池流...     

等离子弧焊接SiCp/Al基复合材料焊缝“原位”合金化分析

采用等离子弧焊焊接SiCp／Al基复合材料,以Ar＋N2为离子气,并以Ti作为合金化填充材料,研究了焊缝“原位”合金化元素Ti对焊缝显微组织的影响。结果表明,采用焊缝原位合金化方法焊接SiC颗粒增强铝基复合材料（sicp／A1MMCs）,可以有效抑制焊缝中针状脆性相Al4C3的形成,并且由于耶的加入,改善了增强相和Al基体之间的润湿性,形成了稳定的熔池,得到以均匀分布的TiN、AlN等为增强相的新型铝基复合材料焊缝,焊接性能得到有效提高。同时还研究了Ti的添加量对焊缝显微组织的影响,结果发现,随着耶含量的增加,焊缝中还生成如Ti5Si3等新的增强相。焊缝“原位”合金化等离子弧焊接是焊接SiCp／Al基复合材料的一种新方法。     

焊接工艺/熔焊

采用等离子弧焊接工艺研究铝基复合材料SiCp／6061A1的焊接性，借助x射线衍射、扫描电镜等手段分析接头组织，着重探讨了在填加和不填加合金化填充材料Ti的情况下，焊接电流、焊接速度对焊缝显微组织及焊接接头力学性能的影响机理。研究表明，在未填加材料Ti时，[第一段]     

电弧超声对SiC_p/AlMMCs焊缝组织与性能的影响

以Ti合金作为填加材料,以氮氩混合气作为离子气,对SiCp/6061Al基复合材料进行电弧超声等离子弧原位合金化焊接,研究了电弧超声对等离子弧焊接头组织和性能的影响.结果表明,在不加超声时,焊缝中新生AlN相呈细长条状,Al3Ti相粗大,TiC,TiN等新生增强颗粒分布不均匀;在加入超声后,焊缝组织细密,TiC,TiN,AlN等增强相呈细小颗粒状存在,数量增加,且分布均匀,Al3Ti相尺寸减小,数量减少,从而有效改善了焊接接头的组织和性能,使焊接接头抗拉强度最大值达到225MPa,比不加超声时提高了约7%.     

SiCp/Al基复合材料等离子弧原位焊接研究

采用等离子弧原位焊接工艺研究了SiCp／Al基复合材料的可焊性。结果表明：以Ti为合金化填充材料，以N2＋Ar为离子气，可以大大减弱SiC颗粒与基体Al之间的界面反应。通过拉伸试验、显微硬度测试、金相观察、扫描电镜、X射线衍射分析，对焊接接头进行了研究。得出焊缝表面的蓝黑色薄膜状物质为AlN和Al的混合物，焊缝中心新生相为AlN、TiN和TiC。探讨了接头力学性能不高的原因，并提出了在等离子弧焊条件下提高SiCp／Al焊接接头质量应采取的措施。     

N2在等离子弧原位焊接SiCp/Al基复合材料中的作用

以0．8mm钛片作为填充材料，采用纯氩和氮氩混合等离子气体对SiCp／Al基复合材料进行等离子弧原位焊接，分析加入的N2对焊缝成形、焊缝组织和性能的影响。结果表明，随氮气体积分数增大，焊缝熔深也相应增大：增加氮气还改善了熔池中的热循环状态和冶金反应，生成TiN、AlN等新的增强相，有效地抑制脆性相的生成，改善了焊接接头的性能。力学性能实验表明，采用Ar＋N2作为离子气进行焊接时，焊缝硬度和强度都有提高。当N2体积分数约占15％时，拉伸强度达到最大值233．5MPa。     

热处理对SiCp/6061Al基复合材料等离子弧焊接头性能的影响

热处理对SiCp/6061Al基复合材料等离子弧原位焊接接头组织与性能的影响较为明显,固溶处理 时效与退火相比,前者对接头的改善作用更佳.经500 ℃固溶处理2 h 12 h时效热处理后,接头组织得到良好的改善,细长的Al3Ti相变为短小棒状,消除了晶间偏析,组织更加均匀;热影响区组织中晶粒均得到比较明显的细化,比较接近母材晶粒的大小,焊接接头强度较未热处理时有了较大提高,达到245 MPa.     

SiC_p/Al基复合材料等离子弧原位焊接研究

采用等离子弧原位焊接工艺研究了SiCp/Al基复合材料的可焊性。结果表明:以Ti为合金化填充材料,以N2+Ar为离子气,可以大大减弱SiC颗粒与基体Al之间的界面反应。通过拉伸试验、显微硬度测试、金相观察、扫描电镜、X射线衍射分析,对焊接接头进行了研究。得出焊缝表面的蓝黑色薄膜状物质为AlN和Al的混合物,焊缝中心新生相为AlN、TiN和TiC。探讨了接头力学性能不高的原因,并提出了在等离子弧焊条件下提高SiCp/Al焊接接头质量应采取的措施。     

Microstructural evolution and its effects on mechanical properties of spray deposited SiCp/8009Al composites during secondary processing

15% (volume fraction) SiC_p/8009Al metal matrix composites(MMCs) prepared by spray co-deposition were hot-extruded and rolled to investigate the effects of porosity and local SiC_p clusters on mechanical properties. The microstructures were examined by using optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The mechanical properties were measured by tensile testing. The experimental results show that lamellar structure is composed of pores and SiC_p clusters and can be improved by secondary processing, enhancing mechanical properties. The main strengthening mechanism and fracture behavior of MMCs were discussed too.     

超声频电弧对SiCp/6061Al等离子弧焊缝微观组织的影响

应用高通滤波器原理设计了一台隔离耦合装置,实现了交流弧焊电源与高频 激励源的隔离与耦合,成功在交流电弧中激励出超声波.以自主研制的A1-5Ti-5Si药芯焊丝为填充材料对SiCp/6061A1基复合材料进行等离子弧原位合金化焊接,在不同频率电弧超声作用下研究了电弧超声频率对焊缝组织的影响.对比0(不加超声),30,40...     

Multi-objective optimization of friction stir welding parameters using desirability approach to join Al/SiCp metal matrix composites

Silicon carbide particulate (SiC_p) reinforced cast aluminium (Al) based metal matrix composites (MMCs) have gained wide acceptance in the fabrication of light weight structures requiring high specific strength, high temperature capability and good wear resistance. Friction stir welding (FSW) process parameters play major role in deciding the performance of welded joints. The ultimate tensile strength, notch tensile strength and weld nugget hardness of friction stir butt welded joints of cast Al/SiC_p MMCs (AA6061 with 20% (volume fraction) of SiC_p) were investigated. The relationships between the FSW process parameters (rotational speed, welding speed and axial force) and the responses (ultimate tensile strength, notch tensile strength and weld nugget hardness) were established. The optimal welding parameters to maximize the mechanical properties were identified by using desirability approach. From this investigation, it is found that the joints fabricated with the tool rotational speed of 1370 r/min, welding speed of 88.9 mm/min, and axial force of 9.6 kN yield the maximum ultimate tensile strength, notch tensile strength and hardness of 265 MPa, 201 MPa and HV114, respectively.     

Surface integrity of milling in-situ TiB2 particle reinforced Al matrix composites

The preparation process and material properties of in-situ TiB₂ particle reinforced Al matrix composites are quite different from conventional ex-situ Al matrix composites (SiC_p/Al composites). Most researches have been carried out mainly focus on the machinability of SiC_p/Al composites, but few studies about the machinability of in-situ TiB₂ particle reinforced Al matrix composites have been published. To address this issue, experimental researches were conducted to investigate the surface integrity (surface roughness, residual stress, microhardness, surface topography, defects) of milling in-situ TiB₂ particle reinforced Al matrix composites in this paper. By examining the machined surface with SEM and EDS for different machining parameters, the influences of cutting speed, feed rate, cutting depth and width on surface integrity were investigated. The results show that feed rate has the dominant influence on surface roughness. As the feed rate increases, the surface roughness increases accordingly. Residual stress decreases and transfers from compressive stress to tensile stress as milling speed gets larger and feed rate decreases. Microhardness variation is not evident below the machined surface. Besides, unlike ex-situ Al matrix composites, pull-out or fractured particles were rarely found on the machined surface of in-situ TiB₂/Al composites.