Mg和Zn对2099合金时效组织与拉伸性能的影响

通过常规力学性能测试和透射电镜微观组织观察,研究2099合金在不同热处理状态(T6和T8)下的微观组织和拉伸性能,以及2099合金中所含少量Mg和Zn对合金组织与性能的影响。结果表明:2099合金在T6峰时效条件下,主要强化相是δ′相、θ′相和T1相;在T8峰时效下,主要强化相是δ′相、T1相和少量θ′相,预拉伸变形促进T1相的析出,提高合金的时效强化效果;Mg的添加促进GP区和θ′相的析出,Zn的添加有利于T1相生成和弥散分布;而Mg和Zn同时添加显著地促进T1相析出,并抑制δ′相的粗化。     

微合金化对Al-Cu-Li-Zr合金拉伸性能和微观组织的影响

通过拉伸测试和TEM观察研究了Mg、Zn、Mn微合金化对Al-Cu-Li-Zr合金力学性能和微观组织的影响。结果表明:与基础合金相比,Mg、Zn、Mn微合金化的Al-3.1Cu-2.1Li-0.1Zr合金T6时效时的强度较高,峰值强度提高约40 MPa,且在低温T8时效时的时效响应速率明显加快,同时具有较低的各向异性。Al-Cu-Li-Zr合金的析出相为大量δ'相、T1相和少量θ'相。T6时效时,微合金元素的添加显著增大δ'相、T1相和θ'相的析出密度,且出现少量S'相。低温T8时效时,微合金元素的添加有效促进δ'相和T1相细小弥散地析出。     

2197铝-锂合金的组织和性能

通过力学性能测试和显微组织观察研究了2197合金组织和性能之间的关系.结果表明:2197合金具有中等强度、各向异性小、热稳定性好等特点;该合金在T8状态下能获得最佳的强度和塑性配合,在T6时效状态以析出少量δ'、θ'和T1相联合强化为主;在2197合金的相组成中T1相析出数量不占主导地位,Al6Mn弥散质点的析出有利于减少各向异性;2197合金中Li含量较低,使其呈现较好的热稳定性.     

微合金化和焊接过程对Al-Li合金强化相影响的综述

Al-Li合金具有密度低、比强度高等优点,是一种综合性能优异的轻质合金,在航空航天等领域被广泛应用和大量研究。综述了第二代Al-Li-Mg系、Al-Li-Cu-Mg系和第三代Al-Li-Cu系合金的性能特点,介绍了Al-Li合金三元T1(Al2CuLi)和二元δ'(Al3Li)、θ'(Al2Cu)这3种强化相的特性,介绍了δ'(Al3Li)和T1(Al2CuLi)初生相的结构特点。众所周知,强化相是影响合金性能的重要因素。结合国内外文献,列举了Al-Li合金微合金化元素对3种强化相以及合金性能的影响规律。Al-Li合金焊接加工时的热量是影响合金强化相的重要因素,热量会加速Al-Li合金中Li元素的流失。最终,提出在开发高性能Al-Li合金方面存在的问题及未来的研究重点。     

Er微合金化对2055 Al-Li合金微观组织及力学性能的影响

研究了0.2%及0.4%Er的添加对2055 Al-Li合金T8态时效(6%预变形+160℃时效)微观组织和力学性能的影响.结果表明,0.2%Er添加显著降低合金强度,但延伸率略有增加.微量Er添加未改变Al-Li合金中时效析出相的种类,主要强化相仍然为T1相(Al2Cu Li)及q'相(Al2Cu),但时效析出相的数量明显减少,同时时效析出的响应速度减缓.2055 Al-Li合金中添加微量Er,凝固时可形成Al8Cu4Er相粒子,这些粒子在后续均匀化及固溶处理时均难以完全溶解至固溶体中,导致固溶基体中Cu含量降低,因而时效时含Cu析出相T1相及q'相含量减少,合金强度降低.     

Ag，Mg合金化对Al-Cu-Li合金时效特性和显微组织的影响

通过力学性能测试和显微组织观察研究微量Ag和Mg对Al-3.5 Cu-1.0Li合金时效特性和显微组织的影响.结果表明:在175℃时效时,单独加Ag不影响合金的时效硬化效果,析出物形貌与Al-Cu-Li合金相似,峰值时效状态下均析出较粗大的T1相和θ'相;单独加Mg加快Al-Cu-Li合金的时效响应,提高合金的时效硬化效果,时效时析出GP区,θ'相和T1相;Ag和Mg同时添加的2050合金中,T1相的析出速度加快,析出密度增大,并以T1相为主要强化相,时效强化效果最大.Ag,Mg添加对合金的不同影响可通过溶质原子与空位、溶质原子与溶质原子之间的相互作用来解释.     

Zn对2195铝锂合金显微组织和拉伸性能的影响

研究了Zn对2195铝锂合金在不同热处理状态(T8，T6)下的显微组织和拉伸性能的影响。结果表明：Zn的存在明显促进了T1相的析出和弥散分布，而且有球形颗粒状含Zn相析出，使合金强度提高：但Zn的加入不改变2195合金的断裂机制，且使合金塑性略有下降。     

Al-4.0Mg-1.5Cu-1.0Li合金中Sc的微合金化行为

通过时效硬化曲线的测量、室温拉伸实验以及时效组织的电镜观察,研究微量钪对Al-4.oMg-1.5Cu-1.0Li-0,12Zr合金时效行为、显微组织和力学性能的影响.结果表明:微量钪的添加能显著增强该合金的时效硬化和强化效果.微观组织分析发现,微量钪的添加可促进Al3Li/Al3(Sc,Zr)复合相与δ'相的弥散析出.通过对合金时效过程中析出相的分析,发现在所研究的合金中析出了Z相,表明微量银不是Z相析出的必要条件.     

Al对IN718合金拉伸性能及稳定性的影响

Al对IN718合金拉伸性能及其稳定性影响的研究结果表明,在标准热处理状态下,Al增加合金中γ"和γ'相析出总量,提高合金室温和680℃的抗拉伸强度,但Al抑制晶界δ相析出,促进Laves相、M7C3相和σ相等在晶界析出,恶化合金的拉伸塑性.经680℃长期时效以后,γ"和γ'相粒子长大,其中高Al合金中析出的γ"/γ'"包覆组织"的长大速率比常规合金中的γ"相小,但两者拉伸强度下降的速度基本相同;合金晶界状态恶化,使室温拉伸塑性明显降低;强化相粒子长大,合金基体的高温强度降低,使680℃拉伸塑性升高.     

Zn元素及时效工艺对2056铝合金微观组织和力学性能的影响

通过显微硬度测试、常规拉伸性能测试、DSC分析和透射电镜观察,研究少量Zn元素及时效工艺对2056铝合金微观组织与力学性能的影响。结果表明:在T6、T8和T3时效状态下,2056合金的抗拉强度(σb)和屈服强度(σ0.2)均比不含Zn合金的高,而伸长率(δ)相差不大,这是因为Zn的添加形成富Zn团簇,促进GPB区的形成,进一步促进S′相的析出,提高合金强度。2056合金在T6、T8峰时效态和T3态下的σb和σ0.2由大到小顺序为T8,T3和T6,时效前的预变形形成大量位错,由于位错和溶质原子强烈的交互作用,形成大量的位错塞积和缠结,增加了T3态合金的强度;在T8态下,大量的位错成为S′相的形核点,使合金形成细小、密集和均匀弥散的S′相,其强度较T6和T3态的得到较大提高。     

Strength and microstructure of 2091 Al-Li alloy TIG welded joint

　The microstructure and tensile properties of TIG welding joints of 2091 Al-Li alloy were investigated both in as-welded and different postweld heat treatment condition. The results show that solution strengthening played an important role in the as-welded condition, though the precipitation strengthening δ′ phase formed already in the as-welded weld metal, but its effect was not apparent due to the lower volume fraction of δ′ phase. So the strength coefficient (φ) of the welded joint/base metal was 64%. After artificially aging heat treatment, the precipitation strengthening effect increased much due to the formation of more δ′ phase and s′ phase. Its φ value was increased up to 89%. The highest strength of the welded joints was obtained after solid solution and then artificially aged heat treatment. Due to the proper size of precipitation strengthening phases and their well distribution, the φ value was increased up to 98%.     

新型耐高压铸造锡青铜的研制

以ZCuSn3Zn8Pb6Ni1合金为基础,通过添加Fe和Co,开发了耐高压铸造ZCuSn3Zn8Pb6Ni1FeCo合金,研究了Fe和Co对合金组织和性能的影响.结果表明,ZCuSn3Zn8Pb6Ni1FeCo合金显微组织与ZCuSn3Zn8Pb6Ni1的相同之处在于均以α-{ Cu,Sn,Zn }为基体,存在硬脆相δ- Cu10Sn3,Pb以单质形式析出;ZCuSn3Zn8Pb6Ni1FeCo合金中还存在α-Fe和γ-Fe析出相,以及CoCu2Sn 、Fe3Co7、Fe4Zn9等硬质相,这些硬质相和基体之间为共格或半共格关系;ZCuSn3Zn8Pb6Ni1合金铸造组织为典型的枝晶组织,晶粒平均直径约3 mm,抗拉强度为180～230 MPa,而ZCuSn3Zn8Pb6Ni1FeCo合金为等轴晶组织,晶粒平均直径为20～60 μm,抗拉强度为400～450 MPa,伸长率在20%以上;ZCuSn3Zn8Pb6Ni1FeCo合金消除了明显存在于ZCuSn3Zn8Pb6Ni1合金中的Sn的宏观偏析.     

铁含量对ZCuSn3Zn8Pb6Ni1FeCo合金组织与性能的影响

采用砂型铸造方法,制备了不同Fe含量的ZCuSn3Zn8Pb6Ni1FeCo合金.利用光学显微镜、拉伸测验、SEM和EDS能谱等分析测试手段,研究Fe含量对合金组织与性能的影响.结果表明:合金组织以α{Cu,Sn,Zn}为基体,并存在硬脆相δ-Cu_(10)Sn_3,铅以单质形式析出;强化析出相主要有α-Fe和γ-Fe,以及CoCu_2Sn、Fe_3Co_7、Fe_Zn_9等;强化机制符合Orowan机制;当铁含量为1wt%时.以细小弥散颗粒状析出为主(平均直径5-15nm),抗拉强度和伸长率分别为350MPa和12.5%;随着铁含量的增加,除细小弥散析出外,较大颗粒状和粗大颗粒析出数量增多,析出物平均直径增大,综合力学性能指标大幅下降;当铁含量为4wt%时,析出颗粒尺寸达到4～10μm,晶界富集粗大析出相,伸长率下降到5%.     

Influence of Zn Content on Microstructure and Tensile Properties of Mg–Zn–Y–Nd Alloy

In the present study, the effect of Zn content on the microstructure and deformation behavior of the as-cast Mg–Zn–Y–Nd alloy has been investigated. The results showed that as Zn content increased, the volume fraction of secondary phases increased. Moreover, the phase transformation from W-phase to W-phase and I-phase occurred. In the as-cast state,W-phase exists as eutectic and large block form. When Zn content increases to 6 and 8%(wt%), small I-phase could precipitate around W-phase particles. Additionally, the effect of Zn content on the tensile properties and deformation behavior varies with the testing temperature. At room temperature, the tensile strength increases with Zn content, whereas the elongation increases initially and then decreases. At 250 °C, as Zn content increases, the tensile strength decreases initially and then increases slightly, whereas the elongation decreases. At 350 °C, the elongation increases with Zn content,whereas the tensile strength decreases initially and then increases slightly.     

EFFECT OF Cu ON MICROSTRUCTURE AND PROPERTIES OF Al-Li ALLOYS

The aging precipitation structure and the properties of Al-Li-Cu-Zr alloys with 3 differentCu/Li ratios have been studied.Experimental results show that the aging hardening of thealloys consists of two steps:The first is strengthened by δ′-phase(δ′+T_1 phase in alloyNo.3),and the second by δ′+T_1 phase(δ′+T_1+θ′phase in alloy No.3).The plate of T_1-phasecan absorb the Li atoms from δ′ particles when the plate bumped into δ′-phase,and therefore,these δ′ phase particles become smaller and gradually disappear.The strength and hardnessincrease with the increase of Cu/Li ratio and cuases a decrease in plasticity.The crack modewould change from transgranular to intergranular.This is due to the precipitation of the equi-librium phases contained Cu at grain boundaries.     

Zn含量对Mg-Gd-Zn合金显微组织与力学性能的影响

研究了3种成分的Mg-11Gd-(1,1.5,2)Zn合金的显微组织和力学性能。结果表明,合金的铸态显微组织均由α-Mg基体、(Mg,Zn)3Gd共晶相和14H型LPSO相组成。铸态组织中(Mg,Zn)3Gd相的体积分数随Zn含量的增加而增大,且其热稳定性不断提高。同时,合金中LPSO相的体积分数也随Zn含量的增加而逐渐增大。合金在常温时的抗拉强度随着Zn含量的增加而降低,其中Zn含量较少的Mg-11Gd-1Zn合金在T6处理后呈现最高的强度和良好的塑性。当Zn含量较多时,合金T6处理的效果却远低于T5处理。随Zn含量的增加,合金在200℃高温下的抗蠕变性能也略有下降,但3种合金的抗蠕变性能都优于WE54合金。     

稀土钇对铸态Mg-8Li-3Al-3Zn合金显微组织和力学性能的影响

镁锂(Mg-Li)合金是现今最轻的金属结构材料,在航空航天及交通运输等领域具有重大的应用价值.但铸造镁锂合金绝对强度低限制了其发展和应用.在Mg-Li二元合金中添加铝(Al)、锌(Zn)和稀土元素钇(Y)三种强化元素制备Mg-Li-Al-Zn-Y五元铸态镁锂合金来提高镁锂合金的力学性能.利用X射线衍射仪(XRD)、扫描...     

固溶-时效对新型高强高淬透性热挤压Al-Zn-Mg-Cu-Zr合金组织与性能的影响

采用力学性能测试、金相观察（OM）、X射线衍射（XRD）、透射电子显微分析（TEM）研究了固溶-时效工艺对Al-6. 6Zn-1. 8Mg-0. 24Cu-0. 23Mn-0. 21Zr（wt%,7046A）合金挤压板带显微组织与力学性能的影响。结果表明:合金适宜的固溶-时效工艺为470℃×1 h固溶随后120℃×24 h人工时效。在此条件下,合金的抗拉强度、屈服强度和伸长率分别为570 MPa、532 MPa和10. 9%。T6态合金的物相组成为Al基固溶体、含Mn和Zr的初晶相以及3～5 nm的η’（MgZn₂）析出相,与此同时,晶界上析出η（MgZn₂）平衡相。合金的强化机制为固溶强化、亚结构强化和时效强化。      

喷射成形Al—Zn—Mg—Cu系高强铝合金的组织与性能

利用喷射成形工艺制备了Al-Zn-Mg-Cu系高强铝合金材料,研究了热挤压工艺与热处理工艺对材料微观组织与力学性能的影响,在峰时效的情况下材料表现出了高的力学性能指标,抗拉强度达到754MPa,屈服强度达到722ＭＰa,断裂延伸率达到8%,与采用传统铸造变形工艺制备的同类合金相比（σb≥610MPa,σ0.2≥580MPa,δ≥4%),性能有了明显的提高。合金性能的提高与其基体中呈弥散分布的Mg7Zn3相有很大的关系,合金的主要强化机制是沉淀强化。     

Microstructural Characteristics and Mechanical Properties of Cast Mg-3Nd-3Gd-xZn-0.5Zr Alloys

The microstructure, aging behavior and mechanical properties of cast Mg-3Nd-3Gd-xZn-0.5Zr (x = 0, 0.5, 0.8, 1 wt%) alloys are investigated in this work. Zn-Zr particles with different morphologies form during solution treatment due to the additions of Zn. As the Zn content increases, the number density of Zn-Zr particles also increases. Microstructural comparisons of peak-aged studied alloys indicate that varying Zn additions could profoundly influence the competitive precipitation behavior. In the peak-aged Zn-free alloy, β’’ phases are the key strengthening precipitates. When 0.5 wt% Zn is added, besides β’’ precipitates, additional fine β₁ precipitates form. With the addition of 0.8 wt% Zn, the peak-aged 0.8Zn alloy is characterized by predominantly prismatic β₁ and scanty basal precipitate distributions. The enhanced precipitation of β₁ should be primarily attributable to the presence of increased Zn-Zr dispersoids. When Zn content further increases to 1 wt%, the precipitation of basal precipitates is markedly enhanced. Basal precipitates and β₁ phases are the key strengthening precipitates in the peak-aged 1Zn alloy. Tensile tests reveal that the relatively best tensile properties are achieved in the peak-aged alloy with 0.5 wt% Zn addition, whose yield strength, ultimate tensile strength and elongation are 179 MPa, 301 MPa and 5.3%, respectively.