细化变质处理对铸造Al-7.5Si-4Cu合金力学性能和组织的影响(英文)

研究了单一和复合Al-5Ti-B、RE和Al-10Sr细化变质剂对砂型铸造Al-7.5Si-4Cu合金力学性能、显微组织、细化变质效果及其金属间化合物变化的影响。结果表明:与单一细化变质处理以及铸态相比,经过添加质量分数为0.8%的Al-5Ti-B、0.1%的RE和0.1%的Al-10Sr细化变质剂复合细化变质处理后铸造Al-7.5Si-4Cu合金的力学性能和显微组织都得到了显著改善。对于单一细化变质处理,加入0.8%的Al-5Ti-B中间合金后,合金的抗拉强度和布氏硬度得到大幅度提高,并且细化了α(Al)相。加入0.1%的RE中间合金后,合金的伸长率得到了最大程度的提高。这是因为RE的加入使铝合金熔液而得到净化,同时改变了金属间化合物的形状。而加入0.1%的Al-10Sr变质剂后,合金的屈服强度得到改善,但其他性能的改善有限。Al-10Sr变质剂对共晶硅具有较强的变质作用,但使得铝合金熔体含气量增加并形成严重的柱状晶组织。利用硅相的平均面积和长宽比描述细化变质效果得到的结论与力学性能和组织分析的结果相同。     

Al-5Ti-1B中间合金对铸造Al-10Mg合金的细化行为

在铸造Al-10Mg合金中添加Al-5Ti-1B中间合金,观察合金的金相组织,测试其显微硬度.结果表明:Al-5Ti-1B对Al-10Mg合金有良好的细化效果,在加入量达到0.1%时,合金平均晶粒尺寸由650 μm变为62μm;随着保温时间的增加,细化效果有所衰退;Al-5Ti-1B的加入使合金的显微硬度提高了近10%.     

电磁搅拌制备的Al-5Ti-1B对6061铝合金显微组织和力学性能的影响

采用电磁搅拌连续铸挤工艺制备Al-5Ti-1B晶粒细化剂,研究了Al-5Ti-1B添加量对6061铝合金显微组织与力学性能的影响。结果表明:添加质量分数为0.1%的Al-5Ti-1B,6061铝合金的显微组织从171μm的粗大枝晶细化成平均直径为70μm的等轴晶,合金的抗拉强度提高了26.47%,伸长率提高了50.91%。随着Al-5Ti-1B的质量分数从0.1%逐渐增加到0.5%,6061铝合金的晶粒进一步细化,抗拉强度和伸长率进一步提高,但晶粒细化效应逐渐减弱。当Al-5Ti-1B添加量为0.5%时,6061铝合金被细化为平均直径为37μm的等轴晶,合金的抗拉强度和伸长率分别为243 N/mm2和10.5%。与未添加Al-5Ti-1B的6061铝合金相比,抗拉强度和伸长率分别提高了42.95%和90.91%。     

Al-Ti、Al-Ti-C中间合金对AZ91D镁合金组织和性能的影响

研究了Al-5Ti、Al-5Ti-0．25C和Al-8Ti-2C中间合金对AZ91D镁合金的组织、力学性能和耐腐蚀性能的影响。结果表明,添加Al-5Ti中间合金使晶粒粗化,而添加Al-5Ti-0．25C和Al-8Ti-2C中间合金使晶粒细化,Al-8Ti-2C中间舍金的细化效果明显且细化后组织细小均匀;添加Al-5Ti中间合金使合金的力学性能降低,而添加Al-5Ti-0．25C和Al-8Ti-2C中间合金均使合金的拉伸强度和伸长率得到了提高;添加Al-5Ti、Al-5Ti-0．25C和Al-8Ti-2C中间合金均使合金的耐腐蚀性能得到了改善。对于AZ91D合金而言,Al-8Ti-2C中间合金是一种良好的晶粒细化剂。     

Al-Ti-B-Sr细化变质剂对A357铝合金组织和力学性能的影响

在A357铝合金熔体中分别加入自制的Al-5Ti-1B-9Sr、Al-5Ti-1B-10Sr和Al-5Ti-1B-11Sr细化变质剂,研究了这三种细化变质剂对A357铝合金显微组织和力学性能的影响。借助于扫描电镜(SEM)、电子探针X射线显微分析(EPMA)等技术分析了加入细化变质剂前后的A357铝合金的微观组织,并对加入细化变质剂前后A357铝合金进行拉伸力学性能试验。结果表明:向A357铝合金中分别添加质量分数0.2%的Al-5Ti-1B-9Sr、Al-5Ti-1B-10Sr和Al-5Ti-1B-11Sr细化变质剂,A357铝合金的抗拉强度分别达到309.18 N/mm2、328.06 N/mm2和314.61 N/mm2;向A357铝合金中分别添加质量分数0.1%,0.2%,0.3%和0.4%的Al-5Ti-1B-10Sr细化变质剂,A357铝合金的抗拉强度分别为326.91 N/mm2、328.06 N/mm2、324.70和296.89 N/mm2,伸长率分别为3.1%、6.4%、3.1%和0.2%。     

Al-5%Ti-0.07%B对Al-Si活塞合金组织和性能的影响

研究了Al-5％Ti-0．07％B中间合金对共晶Al-Si活塞合金组织和力学性能的影响。结果表明，加入Al-5％Ti-0．07％B中间合金能细化共晶团。当加入时间不超过10min时，合金的初晶Si得到细化，硬度和抗拉强度都有所提高，当加入时间超过30min，合金的初晶Si和共晶Si都明显粗化，室温抗拉强度略有降低，硬度和高温抗拉强度略有提高。     

Al-3Ti-3B-1Y合金对Al-9Si合金组织和性能的影响

研究了Al-3Ti-3B-1Y中间合金对Al-9Si-0.4Mg亚共晶合金微观组织和力学性能的影响,并分析了Al-3Ti-3B-1Y中间合金的作用机理。结果表明,加入Al-3Ti-3B-1Y中间合金后,Al-9Si-0.4Mg合金中α-Al晶粒由粗大树枝晶转变为尺寸较为细小的树枝晶,晶粒得到明显细化,共晶Si由长针状转变为颗粒状。Al-9Si-0.4Mg亚共晶合金的力学性能得到明显提高。     

熔铸法制备Al-Ti-C(石墨烯)细化剂及其对Al-6Mg合金力学性能的影响

采用石墨烯、工业纯铝和海绵钛在中频感应炉中熔炼制备了Al-5Ti和Al-5Ti-0.3C铝合金晶粒细化剂(石墨烯进行了粗化处理),通过金相显微镜,扫描电镜,X射线衍射仪,能谱仪和万能拉伸试验机研究了该晶粒细化剂的显微组织及其对Al-6Mg合金的细化效果。结果表明,两种晶粒细化剂均主要由Al相和Al3Ti相组成,在Al-5Ti-0.3C晶粒细化剂的Al基体中含有一定量的碳。两种细化剂分别加入到Al-6Mg合金中,Al-5Ti-0.3C细化效果明显优于Al-5Ti细化剂的。加入质量分数为1%的Al-5Ti-0.3C的细化剂,显著提升了Al-6Mg合金的综合力学性能,抗拉强度和屈服强度分别达到203 N/mm~2和128 N/mm~2,伸长率和断面收缩率分别为11%和15.29%。用石墨烯做碳材料制备Al-5Ti-0.3C晶粒细化剂,其细化机制有待于深入和系统的研究。     

Al-5Ti-1B对铸造702A铝合金组织和性能的影响

铝合金的晶粒大小对合金的力学性能有着显著的影响.本研究采用性能稳定的Al-5Ti-1B合金细化剂对702A铝合金进行细化处理,对比细化剂的不同含量对铸造702A铝合金的微观组织和力学性能的影响.结果表明,在Al-5Ti-1B含量为0.15％时,合金细化剂在细化a枝晶的同时,共晶Si相也得到细化;其力学性能随着细化剂含量的增加,抗拉强度呈上升趋势,综合力学性能得到提高.     

Al-5Ti-1B细化剂对ADC12铝合金铸态组织及性能影响

采用光学显微镜(OM)、扫描电镜(SEM)及力学性能测试等手段研究了Al-5Ti-1B细化剂对ADC12铝合金的显微组织及力学性能的影响。结果表明:当Al-5Ti-1B加入量(质量分数,下同)小于0.2%时,初生α-Al枝晶发达且粗大、是典型的树枝状;当加入0.2%的Al-5Ti-1B时,合金铸态的晶粒细化效果最佳,α-Al枝晶细小均匀,常温抗拉强度提高40.2%,伸长率提高87.5%;而当细化剂加入量超过0.2%时,铸态晶粒细化效果衰退。分析表明金属间化合物TiB_2和TiAl_3共存于铝合金熔体中时可共同成为有效的异质形核核心,促使晶粒细化。     

混合稀土对Mg-5Al-1Si组织及性能的影响

研究了不同组分含量的混合稀土对Mg-5Al-1Si合金高温蠕变性能的影响，对析出相进行了鉴定。研究结果表明，分别加入富镧及富铈混合稀土以后，合金中Mg2Si相得到细化；力学性能检测结果表明，室温及150℃拉伸性能均明显提高。同时，在微量混合稀土及Mg2Si相的综合作用下，含不同混合稀土的Mg-5Al-1Si合金的抗高温蠕变性能均超过AE42。     

Effect of a grain refiner cum modifier on mechanical properties of Al-7Si and Al-11Si alloys

This study evaluates the influence of grain refiners/modifiers on the mechanical properties of the Al-7Si and Al-11Si alloys with an experiment of quantitative and qualitative correlations with the microstructure. Modification of Al-Si alloys with strontium additions and grain refinement with Al-Ti, Al-B and Al-T-B master alloy additions are demonstrated to be efficient on Al-Si alloys. A single master alloy with combined additions of Sr and Ti and/or B was prepared and the microstructure and mechanical properties were studied. The results show that boron rich (Al-3B-Sr and Al-1Ti-3B-Sr) master alloys are more efficient than Ti rich (Al-3Ti-Sr and Al-5Ti-1B-Sr) master alloys considering their combined grain refinement and modification effect on Al-7Si and Al-11Si alloys. However, the presence of Sr does not influence the grain refinement. Similarly, presence of grain refiner does not influence the modification of eutectic Si.     

Microstructure and mechanical properties of rapidly solidified Al-20Si-xFe-3Cu-lMg (x=0 and 5 wt.%) Extradates

The effects of Fe addition and initial powder size distribution on mechanical properties of Al-20Si-3Cu-lMg alloy, prepared by gas atomization and followed by hot consolidation, were studied by using optical microscopy, transmission electron microscopy, X-ray diffractometry, tensile and wear test. The Al-20Si-xFe-3Cu-lMg (x=0, 5) alloys showed homogeneous and refined microstructure. Addition of Cu and Mg to Al-20Si alloy showed increased tensile property due to precipitation hardening. Addition of Fe to Al-20Si-3Cu-lMg increased tensile strength further due to the formation of spherical Al-Si-Fe compound during hot consolidation and phase transformed from the metastable phase. Alloy bars prepared from powder with wide-size distribution showed low tensile strength and wear resistance.     

比压和双细化剂对挤压铸造Al-Zn-Mg-Cu合金组织的影响

采用挤压铸造工艺制备了高速机车用Al-Zn-Mg-Cu合金传动空心轴,研究了比压和Al-5Ti-1B+Al-10RE双细化剂对挤压铸造Al-Zn-Mg-Cu合金传动空心轴微观组织的影响。结果表明,随着比压的不断增大,挤压铸造Al-Zn-Mg-Cu合金空心轴试样中初生α-Al晶粒的形状不断变得圆整,晶粒尺寸不断变小;当比压达到160MPa时,初生α-Al晶粒中粗大的树枝晶基本消失,试样组织为非枝晶组织,试样的平均晶粒直径为25μm,平均等效圆度为0.73;随着双细化剂中Al-5Ti-1B加入量的减少、Al-10RE加入量的增加,试样的平均晶粒直径显著减小,而试样的平均等效圆度变化不大,基本上在0.65～0.75之间;当添加1%的Al-5Ti-1B+3%的Al-10RE时,试样的平均晶粒直径为21μm,平均等效圆度为0.70。     

化学成分对高强Al-Mg-Si合金组织和性能的影响

通过电子拉伸试验机、扫描电镜、透射电镜等研究了5种不同合金成分对高强Al-Mg-Si合金组织和性能的影响。结果发现,5种 Al-Mg-Si合金微观组织、力学性能以及导电性能都强烈依赖于合金中Mg和Si含量。随着Mg、Si含量的增加,合金的抗拉强度增加,同时导电率呈现下降的趋势。Al-0.7Mg-0.5Si和Al-0.6Mg-0.6Si相比,虽然两种合金的Mg、Si原子总量相当,但是由于Mg/Si比不同,导致二者微观组织明显不同,性能存在明显的差异。Ce微合金化使Al-0.7Mg-0.6Si-0.2Ce合金的力学性能和电学性能获得良好的匹配,175 ℃时效4 h的抗拉强度达到325 MPa,同时导电率达到56.2%IACS。     

Grain refinement of Al-3.5FeNb-1.5C master alloy on pure Al and Al-9.8Si-3.4Cu alloy

The refinement potential of Al-3.5 Fe Nb-1.5 C master alloy on pure aluminium and Al-9.8 Si-3.4 Cu alloy has been investigated. Different amounts of Al-3.5 Fe Nb-1.5 C master alloy were added to estimate the optimal addition level. It was found that the addition of Al-3.5 Fe Nb-1.5 C grain refiner can promote significantly the refinement of grains in the pure aluminium, particularly at 0.1 wt.%, with the mean primary aluminium α-grain size reducing to 187±3 μm from about 1-3 mm. Similarly, the microstructural study of the Al-9.8 Si-3.4 Cu alloy die casting at different weight percentages(viz. 0.0 wt.%, 0.1 wt.% and 1.0 wt.%) of Al-3.5 Fe Nb-1.5 C master alloy shows that the Al-3.5 Fe Nb-1.5 C master alloy as a grain refiner is also acceptable for Al-Si cast alloys when the silicon content is more than 4 wt.%. As a result of inoculation with Al-3.5 Fe Nb-1.5 C master alloy, the average grain size of α-Al is reduced to 22±3 μm from about 71±3 μm and grain refining efficiency is not characterized by any visible poisoning effect, which is the major limitation in the grain refinement of Al-Si cast alloys by applying Al-Ti-B ternary master alloys. Mechanical properties such as ultimate tensile strength and yield strength are significantly improved by 9.6% and 9.7%, respectively.     

Mg元素对强流脉冲电子束改性后Al-20Si合金表面微观组织及性能的影响

目的通过添加Mg元素改善Al-20Si合金的组织,提升其表面力学性能。方法运用场发射扫描电镜(FESEM)、显微硬度计及多功能材料表面性能试验仪等一系列检测手段,考察Mg元素对强流脉冲电子束改性Al-20Si合金表面效果的影响,及合金表面微观组织和表面力学性能的变化。结果 Mg元素能与硅相形成更细小的Mg_2Si相来细化初生硅相,同时可改善强流脉冲电子束处理后铝硅合金表面产生的微裂纹。材料表面经强流脉冲电子束改性后,所有的衍射峰发生了宽化及偏移。两组合金铝基体的显微硬度随着脉冲数的增加而逐渐递增,Al-20Si合金铝基体的显微硬度由745.5MPa增加到2170.7MPa,Al-20Si-5Mg合金的铝基体显微硬度由1061.3 MPa增加到2403.6 MPa,Mg元素的添加可提高Al-20Si合金的硬度。另外,通过往复摩擦试验发现,Mg元素及强流脉冲电子束都能提高材料的耐磨性。结论 Mg元素能改善强流脉冲电子束处理后Al-20Si合金表面的微观组织,添加Mg元素后,Al-20Si合金表面的力学性能得到提高。     

Effect of Scandium on Microstructure and Mechanical Properties of Cast Al-Si-Mg Alloy

Microstructural modification and grain refinement due to addition of scandium in Al-6Si-0.3Mg alloy has been studied in this article. It is seen from the microstructure that the dendrites of the cast Al-6Si-0.3Mg alloy have been refined significantly because of addition of scandium. Increasing amount of scandium leads to a greater dendrite refinement. The age hardening effect has been studied by subjecting the alloys containing varying amounts of scandium ranging from 0.2 to 0.6?wt.% to isochronal and isothermal aging at various temperatures for different times. It is observed that addition of scandium is the most effective in suppressing the softening effect during prolonged aging treatment.