搅拌摩擦焊工艺对镁合金焊接接头机械性能的影响

采用不同搅拌摩擦焊工艺焊接镁合金，通过拉伸、三点弯曲试验分析了工艺参数对焊缝机械性能的影响。结果表明，采用合适的搅拌摩擦焊工艺可以成功地焊接镁合金并得到成型美观、质量好的焊接接头，焊缝中因产生充分的塑性流动，弯曲强度高，性能好，在一定参数范围内，随着搅拌头旋转速度R，R/V增加，抗拉强度极限值增加；随着焊接速度V增加，抗拉强度极限值下降，当采用最佳的工艺参数焊接，可得到最大抗拉强度极限值，接近母材的90％。     

Fe-Cu合金的组织、力学性能和电磁性能

针对当前电机普遍存在的能源浪费问题进行导磁导电材料的研究,采用感应加热炉熔炼炉制备Fe-Cu合金,对合金进行正火、淬火+回火处理,通过金相显微镜、扫描电镜等对其微观组织观察研究,并测试其硬度、冲击韧性等力学性能和电磁性能.结果表明,Fe-Cu合金的基体为铁素体,Cu主要分布在奥氏体晶界处.热处理后合金的硬度和冲击韧性发生了变化,随着Cu质量分数的增加,磁导率和电阻率降低,Fe-20%Cu合金的组织均匀,电阻率、起动转矩比常用电机材料铸铝大,满足电机对导磁导电材料的使用要求.     

Fe-Ni-Cu-C合金粗粉注射成形件的力学性能和微观组织

对平均粒度为60μm的Fe-Ni-Cu-C合金粗粉进行了注射成形。分析了烧结温度、保温时间和烧结气氛对烧结件力学性能和微观组织的影响。结果表明,在1 225℃,保温1 h,H2和N2(体积分数)比为1∶3时得到的烧结件具有最好的力学性能,其抗拉强度为360 MPa,屈服强度为171MPa,硬度为54 HRB。     

Microstructure and Mechanical Properties of AZ91D Magnesium Alloy Recycled from Scraps by Hot-press/extrusion

A large number of scraps are produced in the fabrication process of magnesium alloy products. It is necessary to recycle these scraps for the development and scale application of magnesium alloys. In this research, a method for recycling AZ91D magnesium alloy scraps fabricated by hot-press/extrusion was studied. Mechanical properties and microstructure of the recycled specimens were investigated. Microstructural analyses were performed by using the techniques of optical microscopy and scanning electron microscopy. Microstructural observations reveal that the recycled specimens consisted of fine grains when adopting the extrusion temperature of 400-450 ~C, the extrusion ratio of （25-100） ： 1 and the extrusion rate of 0. 10-0. 20 mm/s. Ultimate tensile strength and elongation to failure increased with the increase of the extrusion temperature, the extrusion ratio and the extrusion rate, respectively. Recycled specimens reached the highest ultimate tensile strength of average 361.47 MPa and the highest elongation to failure of average 11.55% when adopting the hot-press, the extrusion temperature of 400_＋5 ~C, the extrusion ratio of 100 ： 1 and the extrusion rate of 0. 15 mm/s. The shape of bonding interface was tightly relation with the ultimate tensile strength. When the bonding interface formed continuous curves, the ultimate tensile strength decreased almost linearly with increasing the average width of the bonding interface. When the bonding interface formed discontinuous curves, the ultimate tensile strength increased almost linearly with the increase the proportion of the fine bonding length accounting for the measured interface length. Ultimate tensile strength of the recycled specimens could be calculated by using the forecastable equation.     

稀土钇对AlZnMgCu合金组织及性能的影响

利用金相显微镜、图象分析仪、ＳＥＭ、Ｘ射线衍射仪等实验手段,研究了单一稀土钇（Ｙ）对航空用铝合金ＡｌＺｎＭｇＣｕ铸态组织和力学性能的影响规律．实验结果表明,少量稀土钇能细化合金的二次枝晶组织,减小共晶化合物尺寸．钇的加入主要和铜（Ｃｕ）、硅（Ｓｉ）等元素结合生成相应的稀土化合物相．研究发现,合金中加入少量钇稀土能有效改善合金的冲击韧性     

Interfacial Microstructure and Mechanical Properties of Al Alloy/Mg Alloy Laminated Composite Plates Fabricated by Equal Channel Angular Processing

KAl(7075)alloy/Mg(AZ31)alloy laminated composite plates were successfully fabricated by the equalchannelangular processing(ECAP)by using route A for 1,2,and 3 passes at 573 K,respectively.After fabrication,the 1-pass ECAPed laminated composite plates were annealed at different temperatures.The microstructure evolution,phase constituent,and bonding strength near the joining interface of Al(7075)alloy/Mg(AZ31)alloy laminated composites plates were evaluated with scanning electron microscopy,X-ray diffraction,and shear tests.The experimentalresults indicated that a 20 μm diffusion layer was observed at the joining interface of Al(7075)alloy/Mg(AZ31)alloy laminated composites plates fabricated by the 1-pass ECAP,which mainly included Al_3Mg_2 and Mg_(17)Al_(12) phases.With the increase of passes,the increase of diffusion layer thickness was not obvious and the form of crack in these processes led to the decrease of bonding strength.For 1-pass ECAPed composites,the thickness of diffusion layer remained unchanged after annealed at 473 K,while the bonding strength reached its maximum value 29.12 MPa.However,after elevating heat treatment temperature to 573 K,the thickness of diffusion layer increased rapidly,and thus the bonding strength decreased.     

镁合金钨极氩弧焊区组织和性能

为了研究镁合金钨极氩弧焊区组织和性能,通过总结、归纳现有的研究方法及研究成果,从影响焊区组织和性能的角度,综述了镁合金钨极氩弧焊技术在国内外的应用研究进展,总结了焊接电参数、焊后热处理、焊接速率、焊剂保护等因素对焊区组织和性能的影响规律.指出现阶段研究存在的问题,并结合我国航空装备的实际生产现状,认为在研究镁合金GTAW时应注重焊接缺陷的研究工作.     

动态时效对Al-Cu-Mg-Ag合金组织与力学性能的影响

对Al-Cu-Mg-Ag新型耐热铝合金进行预时效+中温轧制变形+终时效的动态时效工艺处理,采用硬度测试、拉伸性能测试,结合金相显微组织分析和透射电子显微分析,探究动态时效对其力学性能与微观组织的影响。结果表明：动态时效能够提高合金的时效硬化速率,随着变形量的增大,合金的峰时效时间逐渐减小,峰值硬度逐渐增大。动态时效能够改变晶粒形貌,随着变形量的增大,晶粒的纵横比增大,位错数量增多,强化相数量增多尺寸减小,使得合金强度随着变形量的增大而逐渐增大,但伸长率逐渐减小。变形量为50%合金的强度最高,抗拉强度和屈服强度最大,分别为527.4 MPa和467.0 MPa,伸长率保持在较高值9.1%。     

Ca对Mg-6Al-1Nd合金显微组织和性能的影响

为了研究Ca元素对Mg-6Al-1Nd合金微观组织、力学性能和阻燃性能的影响规律,采用了金属型重力铸造方法制备了Mg-6Al-1Nd-x Ca合金.通过金相显微镜、扫描电镜、万能拉伸试验机和热分析仪等分析测试手段对Mg-6Al-1Nd-x Ca合金的显微组织、力学性能和阻燃性能进行了表征.结果表明:Ca元素的加入可减少β-Mg17Al12含量,生成Al-Ca金属间相;随着Ca质量分数的增加,镁合金试样中的Al-Ca金属相增多,试样的室温抗拉强度和延伸率降低,阻燃性能升高;不含Ca元素的Mg-6Al-1Nd合金的抗拉强度为235 MPa,当Ca元素增加到2.5%时,Mg-6Al-1Nd-2.5Ca合金的抗拉强度仅为154 MPa,但该合金的着火点可达850℃.     

热轧TRIP钢的组织与力学性能研究

采用热轧后控制冷却的工艺制备了TRIP钢，拉伸试验表明，试验钢的性能为：σb=605 MPa，σs=440 MPa，δ=28．4％；对试验钢的组织进行了研究，定量金相检测结果表明，试验钢中残余奥氏体含量为5．6％．     

Mg/Al固相连接接头扩散界面区的显微组织

为了得出铝镁固相连接的最佳工艺参数,获得组织性能较好的连接接头,采用固相连接技术对Mg/Al异种材料进行焊接.利用扫描电镜(SEM)、电子探针(EPMA)、能谱分析仪(EDS)和显微硬度计对扩散界面附近的显微组织、元素分布及硬度分布进行分析,并应用XRD对接头组成相进行了分析.结果表明:界面区形成了显著的新相化合物层,即生成了Mg2Al3、Mg17Al12等脆性金属间化合物,扩散反应区显微硬度范围为HV 280~HV 350,在加热温度为440℃条件下,施加压力为800 N时,组织性能较好,并且保温时间越长,获得的接头组织性能越佳.     

SiCp/AI 复合材料的显微组织与常规力学性能研究

本文研究了流变铸造法制备的 SiCp/LY12和 SiCp/5083Al 复合材料中SiC 颗粒的分布情况,发现在特定的工艺条件下,只有当 SiC 颗粒的体积分数处在一定的范围内。复合材料才能获得良好的 SiC 颗粒分布均匀性:另外,加工工艺对SiC 颗粒的分布也将产生影响.研究结果表明,不同体积分数的 SiC 颗粒均使复合材料的屈服强度得到提高,除时效态 SiCp/LY12复合材料外,其余复合材料的抗拉强度也得到提高,但复合材科的冲击韧性却大大下降。     

Nd含量对AM60镁合金显微组织及力学性能的影响

通过金相分析和电子拉伸等手段研究了稀土Nd的添加对AM60镁合金显微组织和力学性能的影响。结果表明:稀土Nd的加入能显著提高合金的抗拉强度和延伸率。AM60合金中加入Nd后,与Al形成针状的稀土化合物Al11Nd3,使合金中的γ相Mg17Al12数量减少,合金组织得到细化。试验条件下,AM60-1.5%Nd合金具有最好的显微组织和力学性能,但Nd加入量过高,反而使合金的性能降低。     

Microstructure and Mechanical Properties of Ultrafine Grained Mg15Al Alloy Processed by Equal-channel Angular Pressing

An as-cast magnesium alloy with high Al content Mg15Al was subjected to equal-channel angular pressing (ECAP) through a die with an angle of φ= 90? at 553 K following route Bc. It is found that the network β-Mg17Al12 phases in the as-cast Mg15Al alloy are broken into small blocks and dispersed uniformly with increasing numbers of pressing passes. Moreover, many nano-sized Mg17Al12 particles precipitate in the ultra-fine α-Mg matrix. The grains are obviously refined. However, the grain structure is inhomogen...     

平行闸板阀阀座等离子弧喷焊工艺对喷焊层组织及性能的影响

试验研究了平行闸板阀阀座35CrMo等离子喷焊Ni60A合金粉末试样的组织与性能。试验分析结果表明,等离子弧喷焊层冶金结合较好,焊层组织致密、稀释率低;喷焊层是由各种化合物硬质相和基体组成,形成的合金涂层具有良好的耐磨损性能。     

13MnNiMo54/20MnMo异种金属埋弧焊接头性能研究

采用埋弧焊方法对板厚为106 mm的13MnNiMo54/20MnMo进行了异种金属多层多道焊,在检验合格的焊件上截取并制备试样。通过对焊接接头金属进行组织观察、高温拉伸试验以及显微硬度测试研究了异种金属焊接接头的性能。结果表明:中间层焊缝金属组织以细小的块状铁素体为主,表层焊缝金属组织主要为粗大的先共析铁素体和针状铁素体;20MnMo侧HAZ粗晶区是焊接接头的薄弱部位;表层焊接接头金属硬度高于中间层接头金属的硬度,20MnMo侧HAZ粗晶区金属的硬度值最高。     

Mechanical Properties of Phenolic-Resin Composites Reinforced with CF/BF Interlayer Hybrid Fibers

Phenolic-resin composites reinforced with carbon fiber (CF) and basalt fiber (BF) interlayer hybrid fibers plain fabric were fabricated. The tensile strength, compressive strength and interlaminar shear strength of the prepared composites were studied. The results indicated that hybrid fibers reinforced composites possessed the advantages of both CF and BF. When resin content was 35% by volume fraction, the comprehensive mechanical performance of BF/CF reinforced phenolic resin composites reached the optimal values with the warp and weft direction tensile strength, compressive strength and interlayer shear strength being 252 MPa and 487 MPa, 105 MPa and 129 MPa, 21 MPa and 20 MPa, respectively. The scanning electron microscope (SEM) observations showed that the BF/CF hybrid fibers reinforced composites had better interfacial adhesion.     

Mg-Gd-Er-Zn稀土变形镁合金的微观组织与力学性能

为研究Mg-Gd-Er-Zn稀土变形镁合金微观组织与力学性能,通过金属模铸造、固溶处理、热挤压和时效处理工艺过程,制备了Mg-Gd-Er-Zn稀土变形镁合金,并利用金相显微镜(optical microscopy,OM)、X射线衍射仪(Xray diffraction,XRD)、扫描电镜(scanning electron microscopy,SEM)及透射电镜(transmission electron microscopy,TEM)等手段进行表征.结果表明:Mg-Gd-Er-Zn合金的铸态组织主要由α-Mg基体和沿晶界分布的(Mg,Zn)3Gd第2相组成,固溶后生成层片状的长周期堆垛有序(long period stacking ordered,LPSO)结构;经过热挤压变形,合金的晶粒得到显著细化;时效处理过程中,合金中析出纳米级尺寸的β'相.最终时效态合金的室温抗拉强度、屈服强度和伸长率可分别达397.5 MPa、359.0 MPa和6.0%.     

轨道车辆用Al-0.6Mg-0.6Si铝合金焊接技术与接头性能

对轨道车辆车体用新型Al-0.6Mg-0.6Si铝合金型材进行了MIG焊(惰性气体保护金属极电弧焊)试验,利用拉伸试验、光学金相(OM)和扫描电镜(SEM)等方法对焊接接头的成型、气孔缺陷、性能和断口形貌进行了观察和分析.结果表明:Al-0.6Mg-0.6Si铝合金采用70°V型对接形式,使用MIG焊接工艺和表面抛光良好、直径1.2mm的ER5356焊丝,能够获得成型良好的焊接接头.MIG焊接工艺参数为:焊接电流160～180 A,电弧电压18～20V,焊接速度6.0～6.5 mm/s.焊接接头的抗拉强度为266 MPa,断后伸长率为6.1％,断口位于焊缝,断裂形式为韧性断裂,断口呈典型的韧窝结构.     

快速凝固热强Al-4Ti-2V-3La合金的显微结构和力学性能的研究

采用金相（ＯＭ）、透射电镜（ＴＥＭ）、扫描电镜（ＳＥＭ）等先进技术研究了快速凝固Ａｌ－４Ｔｉ－２Ｖ－３Ｌａ合金，确定了基体中弥散分布的细小强化相为单一的Ａｌ２０（Ｔｉ，Ｖ）２Ｌａ相，结构为金刚石立方结构，晶格常数ａ＝１．４７ｎｍ。该性能接近当前较成熟的热强铝合金，说明快凝Ａｌ－Ｔｉ－Ｌａ基合金作为热强铝合金具有潜在的实力。