Microstructures and properties of welded joint of TiNi shape memory alloy and stainless steel

The fracture characteristics of the joint were analyzed by means of scanning electron microscope(SEM).Microstructures of the joint were examined by means of optical microscope, SEM and an image analyzer. The results show that the tensile strength of the inhomogeneous joint of TiNi shape memory alloy and stainless steel is lower than that of the homogeneous joint and a plastic field appears in the heat affected zone on the side of TiNi shape memory alloy. Because TiNi shape memory alloy and stainless steel melted, a brittle as-cast structure was formed in the weld. The tensile strength and the shape memory effect of the inhomogeneous joint are strongly influenced by the changes of composition and structure of the joint. Measures should be taken to reduce the base metal melting and prevent the weld metal from the invasion by O for improving the properties of the TiNi shape memory alloy and stainless steel inhomogeneous joint.     

非连续增强铝基复合材料连接新工艺

介绍几种非连续增强铝基复合材料连接的新工艺，从不同途径改善了接头显微结构和提高接头力学性能，但仍存在一定问题，其目的旨在更多的工作者参与工艺完善和开发研究，加速先进材料焊(连)接技术革新，促进新材料应用．     

铸态铁素体球铁的模拟焊接热影响区组织与力学性能

系统地研究了铸态铁素体球铁的模拟焊接热影响区组织与力学性能，揭示了铸态铁素体球铁的高硅低锰特性对组织与力学性能的影响。指出热影响区的高碳马氏体使其塑性与韧性严重下降，预热４００℃可消除马氏体，并使热影响区的力学性能显著改善。     

蠕墨铸铁同质电弧冷焊焊条的探讨

本文研究了C,Si,Al及Bi对铸铁型焊缝组织及硬度与母材半熔化区宽度的影响。在此基础上确定了焊缝最佳C,Si,Al,Bi含量,进而研究了5种蠕化处理合金及Ti对焊缝石墨形态及基体组织的影响。     

用纯金属Ni作中间层扩散连接铝基复合材料

采用纯金属Ni作中间层扩散连接氧化铝颗粒增强铝基复合材料(Al2O3P/6061Al),探究了连接温度和保温时间对接头显微结构与力学性能的影响.结果表明,连接温度610～620℃时,连接区主要由Al3Ni和Ni在Al中固溶体组成,Al3Ni含量随连接温度升高、保温时间延长而减少;连接温度630℃时,连接区主要由Al2O3颗粒和Ni在Al中固溶体组成,Al2O3颗粒偏聚于接头中心.连接温度620℃、保温时间5～120min条件下,接头抗剪强度68～93MPa,断裂于连接区与母材界面;连接温度630℃、保温时间5～120min条件下,接头抗剪强度93～97MPa,断裂于增强相偏聚区.     

Al2O3P/6061Al复合材料瞬间液相扩散连接

用纯金属作中间层TLP连接颗粒增强铝基复合材料,接头存在增强相偏聚区,是接头力学性能的薄弱区域.控制增强相偏聚区是改善接头力学性能的一种有效途径.文中尝试用Cu,Al金属复合中间层TLP连接Al2O3P/6061Al复合材料,探讨了其接头的显微结构和力学性能特点.结果表明,用Cu,Al金属复合中间层能够控制接头增强相偏聚,改善接头抗剪强度.在连接温度600℃,保温时间60min的工艺条件下,10 μm Al/10 μm Cu/10 μm Al复合中间层接头增强相偏聚明显下降,接头抗剪强度110 MPa;1.5 μm Cu/10 μm Al/1.5 μm Cu复合中间层接头无明显的增强相偏聚,接头抗剪强度123 MPa.     

Microstructural features and properties of plasma sprayed YPSZ/NiCrAlY thermal barrier coating (TBC)

0　IntroductionThermalbarriercoatings(TBCs)arewidelyusedontheturbinebladesforaircraftpropulsionorpowergenerationtoreducethemetallicsubstratetemperature,whichleadstoincreasingengineefficiencyandloweringpollutantemissionsresultingfromallowableincreaseofoperationtemperature[1,2].Today,TBCsareattractingmoreattentionandhavewiderpotentialapplicationstoprotecthightemperaturecomponents.However,thermalbarriercoatingshaveatendencytocrackandspallinserviceduetothermalshockandthermalcyclingbetweenambient…     

低合金奥-贝球铁电弧焊焊条的研究

本文通过等温热处理系统地研究了Ｃｕ，Ｎｉ，Ｍｏ对球铁焊缝金属等温转变，奥－贝化能力及机械性能的影响，并利用Ｘ射线衍射仪，扫描电镜，透射电镜研究了低合金奥－贝球铁焊缝的基体结构，分析讨论了基强韧化机制。在此基础上首次研制成功了Ｎｉ－Ｍｏ低合金奥－贝球铁新焊条，与非合金化奥－贝球铁焊条相比，焊缝金属的奥－贝化能力提高２．５倍，其焊缝与焊接接头的机械性能均满足奥－贝球铁的要求。     

低合金奥－贝球铁电弧焊焊条的研究

本文通过等温热处理系统地研究了Ｃｕ、Ｎｉ、Ｍｏ对球铁焊缝金属等温转变，奥－贝化能力及机械性能的影响，井利用Ｘ射线衍射仪、扫描电镜、透射电镜研究了低合金奥－贝球铁焊缝的基体结构，分析讨论了其强韧化机制，在此基础上首次研制成功了Ｎｉ－Ｍｏ低合金奥－贝球铁析焊分，与非合金化奥－贝球铁焊条相比，焊缝金属的奥－贝化能力提高２．５倍，其焊缝与焊接接头的机械性能均满足奥－贝球铁的要求。