Mg-Li-Al合金的力学性能和阻尼性能

研究了不同锂含量的Mg Li Al合金的力学性能和阻尼性能。结果表明 ,随锂含量的增加 ,Mg Li Al合金的密度和抗拉强度降低、塑性明显提高 ;而Mg Li Al合金的阻尼性能随锂含量的增多和温度的提高而明显增高 ,其中Mg 8Li 1Al合金的室温延伸率为 35% ,室温阻尼性能高达 0 .0 1。Mg 8Li 1Al合金的阻尼明显大于Mg 4Li 1Al合金的阻尼 ,是由于Mg 8Li 1Al合金具有α β双相共晶混合组织 ,α和β相的相界面在循环载荷下产生微滑移 ,而形成相界阻尼 ;而Mg 4Li 1Al合金中只存在α单相组织。     

Ce含量对Mg-Li-Al-Zn合金显微组织和拉伸性能的影响(英文)

制备了Mg-5Li-3Al-2Zn-xCe(x=0-2.5;质量分数,%)铸态合金,并将所得合金分别于300°C和370°C进行均匀化和固溶处理;研究固溶处理后合金显微组织和拉伸性能的变化。结果表明,合金中加入Ce后出现Al2Ce/Al3Ce析出相,此时合金主要由α-Mg、Al2Ce、Al3Ce和AlLi相组成;固溶处理后合金中AlLi和Al-Ce析出相数量减少。析出相的数量与形态对合金的力学性能十分重要,含有1.0%Ce的合金获得了优良的拉伸性能。固溶处理后Mg-5Li-3Al-2Zn-0.5Ce合金的强度和伸长率都得到了大幅度的提高,这是因为合金在固溶处理后由于基体中的溶质原子增加而获得良好的固溶强化作用。     

Mn和Cr对Al-Mg-Si-Cu合金组织及性能的影响

通过金相观察、拉伸性能测试、X射线衍射、扫描电镜及能谱分析,研究了Mn、Cr对Al-Mg-Si-Cu铝合金微观组织及拉伸性能的影响。结果表明：添加Mn和Cr均能促进Al-Mg-Si-Cu合金铸锭形成粗大结晶相化合物,并且添加Mn的合金中形成的结晶相更多;均匀化过程中Mn和Cr均能促进结晶相由Al5FeSi型向Al8Fe2Si型转变,并且同时添加Mn和Cr的促进作用更加显著;添加Mn、Cr均能抑制变形晶粒在固溶处理时发生再结晶和晶粒长大,并且由单独添加Cr、单独添加Mn到同时添加Mn和Cr,抑制作用逐渐增强;添加Cr对合金强化作用有限,而添加Mn能显著提高合金强度。     

Mn,Zr对Mg-Gd-Y合金组织与力学性能的影响

研究了微量Mn、Zr对Mg-13%Gd和Mg-9%Gd-4%Y合金铸态和挤压后的微观组织及力学性能的影响.结果表明:在铸态,含Zr合金的晶粒明显小于不含Zr的合金,而Mn对合金的铸态显微组织影响不大;将Mg-9%Gd-4%Y-0.6%Mn和Mg-9%Gd-4%Y-0.6%Zr合金挤压后,都可以得到非常细小均匀的等轴晶,晶粒尺寸约14 μm;这两个合金在挤压时效态(T5)的力学性能都明显优于WE54合金的,且Mg-9%Gd-4%Y-0.6%Zr合金比Mg-9%Gd-4%Y-0.6%Mn合金性能更好.     

Microstructure and tensile properties of as-extruded Mg-Sn-Y alloys

The microstructure and tensile properties of the Mg-1.0%Sn-xY(x=1.5%,3.0%,3.5%,atom fraction)alloys extruded indirectly at 350℃ were investigated by means of optical microscopy,scanning electron microscopy and tensile test.The mean grain sizes ofα-Mg matrix in the three extruded alloys are 6,8 and 12μm,respectively,slightly increasing with the addition of Y. The relationship between microstructure and strength was discussed in detail.The results show that the addition of Y has little effect on the grain refinement of the as-extruded Mg-Sn based alloys above.The only MgSnY phase is detected in the Mg-Sn-1.5%Y alloy, and the Sn3Y5 phase in the Mg-Sn-3.5%Y alloy,whereas both of them simultaneously exist in the Mg-Sn-3.0%Y alloy.The particle shape of MgSnY and Sn3Y5 phase,inherited from the solidification,has little change before and after hot extrusion.Mg-Sn-3.0%Y alloy has the highest ultimate tensile strength(UTS),305 MPa,by over 50%compared with that of the other two alloys.     

Effect of minor Sc and Zr addition on microstructures and mechanical properties of Al-Zn-Mg-Cu alloys

Three kinds of Al-Zn-Mg-Cu based alloys with 0.22%, 0.36%（Sc＋Zr） （mass fraction, %）, and without Sc, Zr addition were prepared by ingot metallurgy. By using optical microscopy, transmission electronic microscopy and scanning electron microscopy, the effects of microalloying elements of Sc, Zr on the microstructure of super-high-strength Al-Zn-Mg-Cu alloys related to mechanical properties were investigated. The tensile properties and microstructures of the studied alloys under different heat treatment conditions were studied. The addition of minor Sc, Zr results in the formation of Ala（Sc,Zr） particles. These particles are highly effective in refining the microstructures, retarding recrystallization, pinning dislocations and subboundaries. The strength of Al-Zn-Mg-Cu alloys was greatly improved by simultaneously adding minor Sc, Zr, meanwhile the ductility of the studied alloys remains at a higher level. The 0.36%（Sc＋Zr） alloys gain the optimal properties after 465 ℃/h solution and 120 ℃/24 h aging. The increment of strength is mainly due to strengthening of fine grain and substructure and precipitation ofAl3（Sc, Zr） particles.     

Aging behavior of Mg-Li-Al alloys

AgingbehaviorofMg-Li-Alalloys$$$$MaChunjiang;ZhangDi;QinJining;HuWenbin;ShiZhongliang(StateKeyLabofMMCs,ShanghaiJiaoTongUniversity,Shanghai200030,P.R.China)Abstract:AsystemstudyonagingbehaviorandtheinfluenceofheattreatmentonmechanicalpropertyofMg8LilAlandMg11Li3Alalloyshasbeencarriedout.Theresultsshowthatthealloysdescribedabovehaveapparentagingbehaviorandoveraginghappensevenatroomtemperature.(MgLi2Al)phasehasbeenidentifiedwhenhardnessreachesagingpeak.Withtheincreaseofagingtemper…     

Modeling of mechanical properties of as-cast Mg-Li-Al alloys based on PSO-BP algorithm

Artificial neural networks have been widely used to predict the mechanical properties of alloys in material research.This study aims to investigate the implicit relationship between the compositions an...     

Microstructure and properties of modified and conventional 718 alloys

Continuing the effort to redesign IN718 alloy in order to provide microstructural and mechanical stability beyond 650 ℃, IN718 alloy was modified by increasing the Al, P and 13 contents, and the microstructure and mechanical properties of the modified alloy were compared with those of the conventional alloy by SEM and TEM. The precipitation of the grain boundaries of the two alloys is different. The Cr-rich phase, Laves phase and α-Cr phase are easily observed in the modified alloy. The γ＂ and γ＇ phases in the modified alloy are precipitated in a ＂compact form＂. The tensile strengths of the modified alloy at room temperature and 680 ℃ are obviously higher than those of the conventional one. The impact energy of the modified alloy is only about half of that of the conventional alloy. Ageing at 680 ℃ up to 1000 h lowers the tensile properties and impact energy of both the conventional and modified 718 alloys, except increasing the ductility at 680 ℃. It is concluded that the modified alloy is more stable than the conventional one.     

Sm对挤压Mg-6Al-1.0Ca-0.5Mn镁合金微观组织及力学性能的影响

制备了Mg-6Al-1.0Ca-0.5Mn-x Sm(x=0.5,1.5,4.5,质量分数,%)合金,研究了合金的显微组织和力学性能。实验结果表明,随着Sm质量分数的增加,Al_2Sm相主要在晶内析出且体积分数增加,相反Mg_(17)Al_(12)相的体积分数降低;挤压后合金发生动态再结晶,晶粒细化。在室温条件下,含1.5%Sm合金显示了最佳的力学性能,其极限抗拉强度、屈服强度和伸长率分别为316 MPa,148 MPa和21.3%。该合金优异的力学性能主要是由于晶粒细化、Al_2Sm颗粒的弥散强化和减少Mg_(17)Al_(12)相的析出。     

Microstructure,tensile properties and compressive creep resistance of Mg-(5-8.5)%Sn-2%La alloys

The microstructure,tensile properties and compressive creep resistance of permanent-mould cast Mg-(5-8.5)%Sn-2%La (mass fraction) alloys were investigated.The results show that Mg-(5-8.5)%Sn-2%La alloys are all composed ofα-Mg phase, Mg_2Sn and Mg-La-Sn compounds.Compared with those of Mg-5%Sn binary alloy,the grain size and the content of Mg_2Sn compound in Mg-5%Sn-2%La alloy are decreased.With the increase of Sn content in Mg-(5-8.5)%Sn-2%La alloys,the content of Mg_2Sn compound increases,while that of...     

Mn添加对挤压态Mg-Zn-Y-Nd合金微观组织和腐蚀行为的影响

通过光学显微镜,配备能量色散光谱仪的扫描电子显微镜,X射线衍射仪,浸泡法和电化学测试的方法研究了Mn的添加对挤压Mg-Zn-Y-Nd合金在3.5wt.％NaCl溶液中的微观组织和腐蚀行为的影响。结果表明,在研究的Mg-Zn-Y-Nd合金中添加Mn可以诱导Mg3Y2Zn3（I相）沉淀,可以抑制热挤压过程中动态再结晶（DRX）晶粒的粗化。同时,添加了Mn也可以提高合金的耐腐蚀性。不含Mn的Mg-5.6Zn-1Y-0.4Nd合金与含锰1.0 wt.％的Mg-5.6Zn-1Y-0.4Nd合金腐蚀速率分别为18.78 mm·y-1和9.89mm·y-1。而耐腐蚀性的提高主要归因于腐蚀产物层保护性的增强。     

微量Zr对Al-5.8Cu-0.3Mn合金焊接接头组织与性能的影响

采用4047焊丝对Al-5．8Cu-0．3Mn铝合金进行熔化极惰性气体保护焊，利用金相显微镜、透射电镜、显微硬度等检测分析手段研究了Zr对Al-5．8Cu-0．3Mn母材及焊接接头的力学性能和显微组织的影响。结果表明，Al-5．8Cu-0．3Mn合金中添加适量Zr元素可使母材强度提高30MPa，焊接接头强度提高50MPa，同时，细化了母材的再结晶组织和焊缝组织。焊接接头的强度低于母材强度，焊缝区是合金的薄弱处，热影响区强度降低是θ‘相粒子受热粗化所致。     

Microstructure and mechanical properties of Mg-xLi-3Al-1 Ce alloys

Several Mg-xLi-3Al-lCe alloys were prepared by vacuum induction heating. These alloys are Mg-5Li-3Al-lCe, Mg-8Li-3Al-lCe and Mg-14Li-3Al-1C e, respectively. The microstructure and phase composition of these alloys were analyzed by optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractometry. The mechanical properties of these alloys were measured with tensile tester. The results show that, Mg-5Li-3Al-1Ce has a single phase （α） structure, Mg-8Li-3Al-lCe has a double phases （α＋β） structure, Mg-14Li-3Al-1Ce has a single phase （β） structure. And some compounds distribute in the matrix. After being rolled, the grain size of all the alloys is refined. Under the condition of the same content of other alloying elements, the mechanical properties of Mg-5Li-3Al-1Ce are relatively high. With increasing Li content, the strength of both as-cast and as-rolled alloy decrease. For the as-cast alloys, with increasing Li content, the elongation increases. While for the as-rolled alloys, with increasing Li content, the elongation decreases. Ce has refining effect on these alloys.     

多相V-Ti-Ni氢分离合金显微组织与力学性能

研究了多相V_(100-2x)-Ti_x-Ni_x(x=10,15,20)系列氢分离合金的显微组织、硬度和拉伸性能。V_(100-2x)-Ti_x-Ni_x合金铸锭显微组织均由枝晶相V基固溶体和枝晶间相NiTi和NiTi_2组成。随着合金中Ti和Ni的含量增加,枝晶间相在合金中体积占比增大,形成连续网状,阻止枝晶臂的连接。在室温下,合金整体硬度、抗拉强度、延伸率和断面收缩率均随Ti、Ni含量增加而升高。V基固溶体和NiTi_2相是影响3种合金的整体硬度的主要因素。3种合金在室温下均属于脆性材料。合金中NiTi相含量对合金的延伸率有较大影响。     

65Mn弹簧钢的激光焊接组织及性能

采用5kWCO2激光器对65Mn弹簧钢进行焊接处理.利用光学显微镜(OM)、X射线衍射仪(XRI))、扫描电镜(SEM)、显微硬度仪、电子万能试验机及残余应力测定仪对激光焊接接头的显微组织、硬度、抗拉强度、拉伸断口和残余应力进行了研究.结果表明,65Mn弹簧钢经激光焊接后,焊缝中心区组织为等轴晶,近中心区为枝状晶和胞状晶的混合组织,边缘区为少量的胞状晶;在热影响区(HAZ)中,过热区主要是由粗大的针状马氏体组成,相变重合区主要是由较细小的针状马氏体组成,在部分相变区主要由铁索体+珠光体组成.焊接接头主要由α-Fe,Fe3C和FeSi等相组成.焊缝区和HAZ的硬度最高值分别为720HV和770 HV,从HAZ到基材硬度明显下降;焊接接头的抗拉强度平均值为475MPa,焊缝中心区的残余应力平均值为105MPa,热影响区的应力平均值为-60 MPa.     

微量Mn对A1-Mg-Si合金微观组织与拉伸性能的影响

研究了微量Mn对Al Mg Si合金的微观组织与拉伸性能的影响。结果表明 :微量Mn在Al Mg Si合金中主要以粒状α Al15(FeMn) 3 Si2 弥散相的形式存在 ,尺寸为 12～ 2 10nm ,均匀、弥散分布在基体中 ,有效地钉扎位错和亚晶界 ,抑制合金热挤压变形过程中的再结晶 ;均匀化处理过程中微量Mn可促进长针状 β Al9FeSi相向粒状α Al15(FeMn) 3 Si2 相转变 ,这种含Mn的α相弥散颗粒可作为合金时效强化相 β′(Mg2 Si)的非均匀成核位置 ,促进 β′相的析出 ,从而强化合金 ,使合金获得较好的强塑性配合     

New preparation of Mg-Li-Al alloys by electrolysis in molten salt

This work presents a study on electrochemical formation of Mg-Li-Al alloys on an inert electrode (Mo electrode) in a molten KCl-LiCl-AlCl₃-MgCl₂-KF system. It aims at preparation Mg-Li-Al metal alloy directly under an optimal electrolytic parameters. Main factors which affect current efficiency are investigated. We have discussed the co-electrodeposition conditions and the effect of technical parameters on these experiments, and gained a good electrolytic process. The result of calculation shows that co-electrodeposition Mg, Li and Al occurs at the cathode current density higher than 9 A/cm² and electrolytic voltage between 6 to 9 V. And at the optimal parameters, 12-13 A/cm², 620-640 ℃, the highest current efficiency reaches as high as 86 %. Lithium combined with magnesium forms Li_0.92Mg_4.08 and Li₃Mg₇, and aluminum mainly exists in a form of Mg_0.58Al_0.42, distributing in the alpha phases and beta phases.     

喷射成形含锰Al-Zn-Mg-Cu合金的显微组织

为提高Al-Zn-Mg-Cu合金的强度,利用喷射成形的方法制备了含锰Al-Zn-Mg-Cu合金锭,并利用X射线衍射（XRD）、光镜（OP）、扫描电镜（SEM）、透射电镜（TEM）和示差扫描热分析（DSC）研究了其微观组织特征。结果表明：喷射沉积坯主要由晶粒尺寸为5～25μm的细小等轴晶粒、MgZn2和Al6Mn相组成。纳米级的MgZn2颗粒弥散分布于基体,而平均尺寸为5μm的Al6Mn一次相颗粒沿晶界析出。沉积合金中也发现了少量的CuAl2,Al3Zr和共晶组织。沉积坯中缩孔疏松的体积分数约为12%。DSC分析结果说明大部分溶质原子在喷射成形过程中析出,在450℃以下的加热过程中没有明显的热反应发生。随着退火温度的升高,基体晶粒和Al6Mn颗粒单调长大,但Al6Mn颗粒的长大速率显著低于基体晶粒的长大速率。当退火温度高于375℃时,基体晶粒迅速长大。