Microstructure and properties of 2618-Ti heat resistant aluminum alloy

1　INTRODUCTIONAluminumalloy 2 6 18isaheat treatableAl Cu Mg Fe Niforgingalloywhichiswidelyusedinair craftenginecomponentsandautomobileindustries[1] .ItisaheatresistantstructurematerialfabricatedbyI/Mtechnique .TheadditionofsmallamountofFeandNiproducesmicrostructuralstabilityunderther malexposure .Themain precipitatesarecoherentGuinier Preston Bagaryatskii (GPB )zoneswhichformrapidlyonagingattemperaturesuptoatleast2 0 0℃andsemi coherentS′(Al2 CuMg) phasewhichcanapparentlystrength…     

Effect of Cu on microstructure and mechanical properties of 2519 aluminum alloy

The effect of Cu on the microstructure and mechanical properties of 2519 aluminum alloy was investigated by means of tensile test, microhardness test, transmission electron microscopy, and scanning electron microscopy. The results show that when the content of Cu is less than 6.0%, the strength of 2519 aluminum alloy increases with the increase of Cu eontent; when the content of Cu is more than 6.0%, the strength of the alloy decreases. The hardening effect of the aged alloy is accelerated at 180℃ and the time to peak age is reduced, but the plasticity of the alloy gradually decreases with the increase of Cu content. However, the hardening effect of the aged alloy decreases with the increase of Cu as the content of Cu is over 6.0%. The optimal content of Cu of 2519 aluminum alloy is 6.0%, at which the alloy has best tensile strength and plasticity.     

2219-T87铝合金搅拌摩擦焊接头组织与力学性能

采用搅拌摩擦焊方法对8mm厚2219-T87铝合金进行了焊接.对接头的宏观形貌、微观组织、显微硬度及断口形貌进行了分析.结果表明,焊核区为细小的等轴晶粒,晶粒尺寸远小于母材;热机影响区发生了弯曲变形;热影响区组织出现了明显粗化.前进边热机影响区和焊核区形成明显分界线,后退边相对模糊.搅拌摩擦焊对接头各区域沉淀相分布形态有重要影响.接头室温拉伸强度可以达到母材的70%以上.沿焊缝横截面的显微硬度的分布显示,硬度最低点位于后退侧热影响区区域,断裂位置位于后退侧热影响区处,接头的断裂形式为韧性断裂.     

Microstructures and mechanical properties of 2014 aluminium alloy forgings made by a new process

1　ＩＮＴＲＯＤＵＣＴＩＯＮＳｔｒｉｃｔｅｒａｎｄｓｔｒｉｃｔｅｒｒｅｑｕｉｒｅｍｅｎｔｓｏｎａｌｕｍｉｎｉｕｍａｌｌｏｙｆｏｒｇｉｎｇｓａｒｅａｌｗａｙｓｂｅｉｎｇｐｕｔｆｏｒｗａｒｄｂｅｃａｕｓｅｏｆｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｍｏｄｅｒｎａｅｒｏｓｐａｃｅｔｅｃｈｎｉｑｕｅ ,ｎｏｔｏｎｌｙｆｏｒｔｈｅｈｉｇｈｓｔｒｅｎｇｔｈ ,ｌｏｗｄｅｎｓｉｔｙ ,ｂｕｔａｌｓｏｆｏｒｔｈｅｈｉｇｈｄｕｃｔｉｌｉｔｙ .Ｔｈｅ 2 0 1 4ａｌｌｏｙｉｓａｓｏｒｔｏｆｈｉｇｈｓｔｒｅｎｇｔｈａｌｕｍｉｎｉｕｍａ…     

余热热处理对Al-Si-Cu合金铸件组织和性能的影响

研究了余热热处理工艺对Al-Si-Cu合金中Cu元素的固溶效果、共晶Si颗粒形貌及尺寸变化、以及该工艺对合金铸件力学性能的影响.结果表明,余热热处理工艺条件下,铸件可以在更短的时间内获得理想的固溶效果.通过分析铸件微观组织显微可知,余热热处理工艺可以通过缩短固溶处理时间有效地抑制共晶Si颗粒的粗化,在4h的固溶处理中Si颗粒平均尺寸持续减小且未出现粗化趋势.采用相同工艺参数,余热热处理工艺条件下制备的单铸试棒抗拉强度比传统T6热处理工艺提升约15%.     

Cu含量对压铸铝硅合金组织和性能的影响

为研究Cu含量对压铸铝硅合金组织和性能的影响,采用光学显微镜(OM)、扫描电镜(SEM)和能谱仪(EDS)观察了显微组织形貌,并进行了相成分分析。结果表明：A356合金压铸组织中主要是条片状的Si相,添加Cu后,合金中出现Al2Cu相,该相分布在Si相四周及晶界上;随着Cu含量的升高,Si相由条片状变为团聚的骨骼状,除主要强化相Al2Cu相以外,还生成了强化相W相(AlxMg5Si4Cu4);向压铸合金中添加Cu后,合金强度得到了较明显提升,但Cu过高会明显降低合金的塑性。     

时效对超高强含Sc铝合金组织和性能的影响

采用维氏硬度测量、室温拉伸性能测试和显微组织结构分析,研究了不同时效制度下Al-Zn-Cu-Mg-Sc-Zr合金的力学性能、腐蚀性能和显微组织.结果表明,该合金具有显著的时效硬化效应,随时效温度的升高,合金达到时效硬度峰值的时间缩短.合金适宜的时效制度为120℃24h.此时,合金的抗拉强度、屈服强度、伸长率和维氏硬度分别为696N/mm2、654N/mm2、11.1％和211.2HV.合金中主要强化相为GP区和η'相,主要强化作用为沉淀强化及弥散强化.时效过程中Al3Sc和Al3(Sc,Zr)质点表现出较强的热稳定性;合金抗晶间腐蚀能力随时效时间的延长而增强.     

增强体形貌对高熵合金增强铸铝合金组织及性能的影响

本文采用机械合金化工艺制备了两种不同形貌特征的高熵合金（Al0.25Cu0.75FeCoNi）颗粒,一种为椭球状颗粒（平均粒径为53μm,无过程控制剂）;另一种为片状颗粒（平均粒径15μm,有过程控制剂）。采用挤压铸造工艺制备了低体积分数（颗粒含量为5 vol.%）的高熵合金颗粒增强铸造铝合金材料,重点分析了不同增强相形貌对复合材料的组织和力学性能的影响规律。结果表明：在复合材料预制块制备过程中,椭球状高熵合金粉体与铝粉容易混合均匀,而片状高熵合金粉体之间易发生团聚。椭球状颗粒与片状颗粒增强的复合材料的抗拉强度分别达到162MPa和174MPa,比铸铝合金实验基体分别提升了12.5%和 20.8%,但伸长率较铸铝合金基体却发生了明显下降。断口分析表明,椭球状颗粒增强复合材料的断裂以基体的撕裂为主;而片状颗粒增强复合材料则以团聚颗粒的破裂为主。     

Microstructures and mechanical properties of high strength Mg-Zn-Mn alloy

The microstructures and mechanical properties of a new Mg-6%Zn-1%Mn(mass fraction) wrought magnesium alloy were studied,which could be extruded smoothly at 310-330℃with a complete dynamic recrystallization.After solution treatment one and two-step aging techniques were used.All as-aged microstructures contained two types of dispersed phases:β' phases and pureα-Mn particles.The two-step aging had a better strengthening effect than the traditional one-step aging,and the strength value achieved by the two-s...     

7B05铝合金搅拌摩擦焊接头的微观组织和力学性能

采用搅拌摩擦焊双面焊接工艺焊接42 mm厚7B05-T5铝合金型材,利用金相组织观察、显微硬度测定、拉伸能测试等方法研究了搅拌摩擦焊接头的微观组织特征和力学性能。结果表明,焊核区由于发生了动态再结晶,其组织为细小的等轴再结晶组织;焊缝两侧的热机影响区受力和热的双重作用,组织发生一定程度的变形和回复;热影响区组织和母材相似,受热循环作用发生了粗化。力学实验表明,接头的抗拉强度达303 MPa,为母材的90%,拉伸试样均断裂于近缝区热影响区,这与显微硬度分布测定的热影响区软化区位置一致。     

Effects of Sc and Mn on microstructures and mechanical properties of Mg-Gd alloy

Two alloys of Mg-12.4Gd and Mg-12.5Gd-0.8Sc-1.4Mn were prepared. Hot extrusion and T5 heat treatment were conducted, and then the mechanical properties of the two alloys were tested at room and high temperatures. The effects of Sc, Mn on the microstructures of Mg-12.4Gd were investigated by optical microscopy, scanning electron microscopy and transmission electron microscopy. The results demonstrate that after hot-extrusion the alloying with Sc, Mn can efficaciously refine the grains of Mg-12.4Gd alloy; and increase the elongation at room and high temperatures after T5 heat treatment. But the strength at high temperature is not obviously improved.     

Mechanical properties and microstructures of a wrought AZ91 alloy

Effects of hot plastic deformation on microstructures and tensile properties of AZ91 alloy were investigated. Compared with as-T4 microstructures, the as-extruded samples of AZ91 alloy with fine grains exhibit better strength and ductility due to dynamic recrystallization. The succeeded rotation forging also provides freer grains while the strength increases, but the elongation decreases. Simultaneously, wrought AZ91 alloy shows more balance properties than as-T4 condition ones. An interesting elongation of 228.5% is attained in the as-extruded AZ91 alloy in spite of the coarse grains with the size of 85 μm. The two-step method enhances the superplastic property of AZ91 alloy. The microstructure is still keeping the same scale of grains after superplastic testing.     

Mg-5Zn-3Al-0.2Mn铸造合金的组织和室温力学性能

研究了砂型铸造Mg-5Zn-3Al-0．2Mn合金的显微组织，发现其主要相组成为δ-Mg基体相和τ（Mg12（Al，Zn）49）化合物相，τ相以半连续网状骨骼形态沿δ相的晶界分布。实验合金中加入少量Sr，Ti，B元素后，合金组织细化，τ相形态转变为断续的短条状或粒状，并且分布更加均匀。在本实验条件下，当炉前加入0．06％Ti、0．012％B、0．1％Sr时，合金的组织形态得到显著改善，合金的室温力学性能最佳。不同温度下对Mg-5Zn-3Al-0．2Mn合金进行的固溶处理实验发现，在335℃固溶17h淬火后，合金的室温抗拉强度和塑性得到了大幅度提高；在343℃固溶17h淬火后，合金组织完全转变为单相固溶体，合金的室温力学性能较好，巩为245MPa，δ为12％。     

Tensile and fatigue properties of aluminum alloy sheet 6022

Tensile and fatigue tests were performed on aluminum alloy 6022 T4E29 and T6 sheet specimens in ambient air. The tensile and fatigue properties were compared with other commercial aluminum alloys. The results showed that 6022 alloy has high fatigue strength and good ductility with moderate tensile strength.     

挤压铸造Al-5.0Cu-0.6Mn-0.5Fe合金的显微组织和力学性能

采用拉伸性能测试、定量金相分析、扫描电镜等手段研究挤压铸造Al-5.0Cu-0.6Mn-0.5Fe合金的显微组织和力学性能,分析挤压压力对合金的力学性能和显微组织的影响。结果表明:当挤压压力从0增大到75 MPa时,合金的抗拉强度(σb)和伸长率(δ)都显著增加。当挤压压力为75 MPa时,铸态合金的抗拉强度为298 MPa,伸长率达17.6%;经T5热处理后,合金的抗拉强度为395 MPa,伸长率为14.2%。当挤压压力从0增大到75 MPa时,α(Al)二次枝晶间距减小了69%,θ相(Al2Cu)和富Fe相的体积分数略有降低,针状β-Fe相消失,同时晶界处汉字状α-Fe相由连续的汉字状变成分散、细小的骨骼状。     

Microstructure and properties of vacuum counter-pressure cast aluminum alloy

As a special casting process, counter-gravity casting has many advantages especially in producing thin-wall complicated castings and has widely been used in industry [1]. In recent ten years, various different counter-gravity casting processes have been continuously developed such as vacuum suction casting, low-pressure casting and counter-pressure casting [2-4] et al. Vacuum counter- pressure casting is a new kind of counter-gravity casting technology that was developed in recent years. It ha…     

Microstructures and mechanical properties of Al-Mg and Al-Zn-Mg based alloys containing minor scandium and zirconium

1　INTRODUCTIONAddingofminorMn ,Cr ,Ti,B ,Zr ,Sc ,Agintoaluminumalloyscanremarkablychangethemi crostructuresandpropertiesofaluminumalloys[18] .Amongthem ,theeffectofminorScandZrhasre ceivedspecialattention .Onthe 1stInternationalScandiumConferenceheldinMoscowin 1994 ,Rus sianmetallurgistsdescribedtheapplicationprospectofaluminumalloyscontainingScinaerospace ,aviation ,warshipsandnuclearindustry ,whichhasstimulatedmanyindustrialcountries’researchinterestinthiskindofalloys .Atpresent…     

搅拌铸造SiC_p/2024铝基复合材料的显微组织与力学性能

利用搅拌铸造?热挤压工艺制备SiCp/2024铝基复合材料板材,研究该复合材料铸态、热挤压态和热处理态的显微组织及力学性能。结果表明:SiC颗粒较均匀地分布于铸锭中,大部分SiC颗粒沿晶界分布,少数颗粒分布于晶内,晶界粗大的第二相呈非连续状分布;复合材料经热挤压变形后,显微孔洞等铸造缺陷明显消除,破碎的晶界第二相及SiC颗粒沿热挤压方向呈流线分布,复合材料的强度和塑性显著提高;对热挤压板材进行(495℃,1h)固溶处理+(177℃,8h)时效处理后,其抗拉强度达430MPa,此时的主要析出强化相为S′(Al2CuMg);热挤压变形有利于改善SiC颗粒与基体合金的界面结合,热处理SiCp/2024铝基复合材料的主要断裂方式为基体合金的延性断裂、SiC颗粒断裂和SiC/Al的界面脱粘。     

Effects of Ag addition on mechanical properties and microstructures of Al-SCu-0.5Mg alloy

The mechanical properties and microstructures of Al-8Cu-0.5Mg alloy with and without Ag addition were studied at both room- and elevated-temperatures. The results show that the alloy with Ag is strengthened by a homogeneous distribution of coexistent θ＇ and Ω precipitates on the matrix （001） and （111） planes, respectively, whereas the alloy without Ag by θ＇ precipitates only. The small size and high volume fraction of θ＇ and Ω precipitates in the Ag-containing alloy improve the tensile strength and yield strength, especially those at the elevated temperatures. However, it is also responsible for the decrease in elongation, compared with the alloy without Ag, which is due to the microcracks initiated from the inherent incompatibility between the particles and the AI matrix during deformation.     

原位自生Ti2AlC增强TiAl合金组织与力学性能影响研究

采用真空电弧熔炼炉制备了原位自生Ti2AlC增强Ti-48Al-2Cr-2Nb合金,研究了CNTs含量对TiAl基合金的组织演变和力学性能的影响。结果表明,随着CNTs的增加,合金的凝固路径向高Al方向移动,γ相含量增多,与此同时片层组织逐渐细化,Ti2AlC的长径比逐渐减小。在固溶强化、细晶强化以及Ti2AlC析出相强化的作用下,合金的力学性能得到显著提高。随着CNTs含量的增加,合金的维氏硬度由358.4±19.2 HV提高到了428.5±23.1 HV。合金的室温压缩强度和高温压缩强度均随着CNTs的增加先增加后减小。当CNTs添加量为3.0 at.%时,其室温压缩强度和最大应变分别达到1890.61 MPa和29.09%,分别提升54.95%和28.31%。在800 ℃压缩中,合金的硬化和软化效果受CNTs含量影响,3.0 at.% CNTs的合金表现出最高的压缩强度,相比于未添加CNTs时提升约31.42%,而4.5 at.% CNTs的合金在不影响压缩强度的情况下表现出较好的软化效果。