喷射成形Al95Cu2Fe1Ni1Ce0.5Zr0.5合金的微观组织形成机制及拉伸 …

采用喷射成形技术制备了Ａｌ９５Ｃｕ２Ｆｅ１Ｎｉ１Ｃｅ０．５Ｚｒ０．５合金材料，研究了该合金快速凝固组织的形成机制，并以沉积态及热挤压态材料的拉伸性能进行了测试，结果表明：喷射成形快速凝固技术显著地细化了合金组织，预成菜毛坯组织的微观不均匀使沉积态材料的综合力学性能降低，热挤压工艺可改善合金的均匀性，提高材料性能。     

喷射沉积Al－2．15Li－1．28Mg－1．26Cu－0．10Zr合金的显微组织与拉伸性能EI

采用新型的喷射沉积快速凝固工艺制备了Ａｌ－２．１５Ｌｉ－１．２８Ｍｇ－１．２６Ｃｕ－０．１０Ｚｒ合金，对合金的显微组织与拉伸性能进行了研究。实验结果表明，沉积态实验合金组织为大量细小、均匀的等轴晶，经热挤压后晶粒呈“砖块”状形貌特征，在晶界上不易观察到破碎氧化物。时效析出不规则形状的δ＇相粒子、球壳状β＇－δ＇复合沉淀相及Ｓ＇相。喷射沉积Ａｌ－Ｌｉ合金经１９０℃／２０ｈ时效后达到峰时效状态，此时材料的综合性能最优（σ＿ｂ＝５２８ＭＰａ，σ＿（０．２）＝４２０ＭＰａ，δ＝１２％）。与粉未冶金Ａｌ－Ｌｉ合金相比，材料的塑性明显改善。     

喷射沉积Al－2．15Li－1．28Mg－1．26Cu－0．10Zr合金的显微组织与拉伸性能

采用新型的喷射沉积快速凝固工艺制备了Ａｌ－２．１５Ｌｉ－１．２８Ｍｇ－１．２６Ｃｕ－０．１０Ｚｒ合金，对合金的显微组织与拉伸性能进行了研究。实验结果表明，沉积态实验合金组织为大量细小、均匀的等轴晶，经热挤压后晶粒呈“砖块”状形貌特征，在晶界上不易观察到破碎氧化物。时效析出不规则形状的δ＇相粒子、球壳状β＇－δ＇复合沉淀相及Ｓ＇相。喷射沉积Ａｌ－Ｌｉ合金经１９０℃／２０ｈ时效后达到峰时效状态，此时材料的综合性能最优（σ＿ｂ＝５２８ＭＰａ，σ＿（０．２）＝４２０ＭＰａ，δ＝１２％）。与粉未冶金Ａｌ－Ｌｉ合金相比，材料的塑性明显改善。     

结构材料喷射成形技术与雾化沉积高温合金

喷射成形是利用快速凝固方法直接制备金属材料坯料或半成品的先进材料制造技术 ,喷射沉积高温结构材料的冶金性能好、生产效率高、成本低 ,因而在近几年得到了迅速发展 .本项研究的主要目的是要通过喷射成形工艺参数的调整、最大限度地直接减少喷射成形坯中的孔隙度 ,进而得到优质坯料 .利用优化的雾化喷射沉积技术制备了多种高温合金沉积坯 ,沉积坯整体致密、晶粒细小、组织均匀、无宏观偏析、含气量低、力学性能提高 .还简要地比较了喷射成形高温合金与用常规铸锭冶金工艺和粉末冶金工艺制备高温合金的异同 ;总结了航空材料研究院喷射成形高温材料近年来的研究状况 ,包括专用高温材料喷射成形装置和技术及其应用 .     

喷射成形高温合金的研究与应用

喷射成形是一种近终形快速凝固技术,综述了喷射成形高温合金的研究和应用.研究表明,喷射成形高温合金成分均匀、无宏观偏析、晶粒细小、气体夹杂含量低,力学性能与粉末合金相当,高于变形合金,冷热加工性能明显改善,且成本较低.喷射成形高温合金技术通过20多年的发展取得了较大的进步,包括纯洁金属喷射成形(CMSF)和纯洁金属成核铸造(CMNC).喷射成形高温合金的应用主要是管件、环形件和盘件.最后对喷射成形涡轮盘材料FGH96组织作了初步的研究.     

喷射成形高锰ZA35合金的工艺及组织研究

利用优化工艺参数的喷射成形技术制备含Mn3.5%(质量分数,下同)的ZA35合金坯,比较了铸态和喷射成形态合金的微观组织.研究表明:喷射成形态合金晶粒细小,组织分布均匀;元素Mn在铸态组织中主要以大量富Mn独立硬化相分布于晶界或晶界附近,喷射成形合金组织中富Mn相消失,元素Mn溶入基体,固溶度明显提高.元素Mn在铸态和喷射成形态合金基体中分布规律一致,即在α富铝相中的固溶度显著高于在η富锌相中的固溶度.热挤压后,喷射成形3.5%Mn-ZA35中有类似纳米级晶须状和颗粒状的MnAl6析出.     

喷射成形镍基高温合金的研究进展

喷射成形是一种新型快速凝固技术,采用这项技术制备的镍基合金,具有细小,球状的晶粒和均一的组织,从而提高其性能,综述了喷射成形镍基高温合金的发展概况及组织,性能特点。     

喷射沉积AlZn12Mg2Cu2合金的组织结构及力学性能

用喷射成形技术在较低雾化压力下沉积了AlZn12Mg2Cu2合金，对其组织结构用光学显微镜和透射电子显微镜进行了观察和分析，发现：在本喷射成形工艺条件下，可以形成高致密度的具有等轴晶粒的均匀合金，晶粒尺寸在30～60μm范围内，在晶内和晶界处有MgZn2相的析出，对制备的材料经济压比为7.7:1条件下的热挤压和T6时效处理后进行了力学性能测定，结果显示屈服强度（бUS）为740MPa，抗拉强度（бUTS）为753MPa，延伸率（δ）为8.6%。     

离心雾化喷射成形工艺对锌基合金成形性和组织结构的影响

采用先进的离心雾化喷射成形技术研制具有良好耐磨性能的锌基合金环形件 ,研究在这种新工艺条件下锌基合金的成形性和组织特征 .研究结果表明 ,喷射沉积环形件的形状比较规整 ,厚度比较均匀 .沉积态材料组织细小、均匀 .工艺条件对喷射沉积锌基合金的质量有明显影响 .采用在基底和沉积层之间加过渡层金属的办法 ,可获得界面冶金结合良好的复合金属材料 .     

喷射成形过共晶Al-Si合金材料的研究现状

过共晶Al-Si合金具有较高的强度、较低的密度和热膨胀系数、良好的耐磨性和耐蚀性,在汽车、造船、航空航天及其他制造行业广泛应用.但当合金中Si含量太高时,合金组织粗大、偏析严重,同时材料的强度、塑性急剧降低而失去使用价值.喷射成形技术是一种全新的材料制备技术,具有快速凝固技术的基本特征,同时还具有生产工序简单、氧化和污染小等优点,在国外已经在特殊钢、高温合金、铝合金和铜合金等方面进行了产业化应用.但利用喷射成形技术来制备和生产过共晶Al-Si合金材料还很不成熟,有许多问题还没有得到妥善的解决,作者提出两点建议来进一步改善过共晶Al-Si合金材料的性能(1)在喷射成形过共晶Al-Si合金中添加微量稀土元素;(2)利用喷射共沉积技术制备过共晶Al-Si合金为基体的纤维增强复合材料.     

La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的储氢性能研究

针对两种新型稀土型储氢合金La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2的储氢特性进行研究分析。实验表明,相同温度下,La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的PCT曲线基本重合,且都具有优良的吸氢动力学性能;相比之下,后者的滞后系数要小于前者,吸氢量较大,吸氢速率也较快,故其储氢性能较优。300次吸放氢循环实验结果表明,La0.5Y0.5Ni4.8Al0.2合金的吸氢动力学性能虽然略有下降,但抗粉化性能较好。     

Enhanced tensile properties in a Mg-6Gd-3Y-0.5Zr alloy due to hot isostatic pressing (HIP)

Hot isostatic pressing (HIP) was applied to Mg-6Gd-3Y-0.5Zr (GW63) alloy to reduce shrinkage porosity, thus, to enhance the integrity and reliability of castings. During HIP process, shrinkage porosity was closed by grain compatible deformation and subsequent diffusion across the bonding interface. The amount of initial shrinkage porosity was the key factor for shrinkage porosity closure. HIP was testified to be effective on shrinkage porosity reduction in GW63 alloy due to its relatively narrow solidification range and resultant low content of initial shrinkage porosity in most sections, leading to higher tensile properties both in as-cast and cast-T6 condition. The improvement in tensile properties was mainly because of shrinkage porosity reduction and resultant effective rare-earth (RE) elements homogenization and precipitation strengthening.     

时效温度对Mg-12Gd-3Y-1Sm-0.5Zr合金组织和力学性能的影响

采用X射线衍射、光学显微镜、透射电子显微镜、显微硬度和拉伸性能测试等手段,研究时效热处理温度对Mg-12Gd-3Y-1Sm-0.5Zr合金组织和性能的影响。结果表明,Mg-12Gd-3Y-1Sm-0.5Zr合金在200,250℃和300℃峰时效时,晶粒大小随时效温度的升高而逐渐增大,晶内颗粒状的第二相数量增多,硬度峰值出现的时间逐渐缩短。合金时效温度在200,250℃时,析出相为β′相,时效温度在300℃时,析出相为β相。合金在250℃峰时效时力学性能最优。在200,250℃峰时效热处理的合金在从室温到200,250℃和300℃拉伸过程中抗拉强度随拉伸温度的升高先升高后降低,出现了抗拉强度反常温度效应,而在300℃峰时效热处理后的合金未出现该反常现象。     

Aging behavior of 359-type Al–9%Si–0.5%Mg casting alloys

The present study investigated the influences of aging temperature and time on the tensile properties and quality indices of 359-type Al–9%Si–0.5%Mg casting alloys. These alloys are still not widely used by most foundrymen in spite of the fact that they are extremely promising for several fields of engineering applications because of their superior strength. For the purposes of validating their use in industrial applications, a solid data base was created, based on the present study, correlating the tensile properties and the quality indices of these alloys with the aging parameters. Quality charts were used as an evaluation tool for selecting the optimum aging conditions for developing high strength and optimum quality in 359 casting alloy. Aging at a low temperature was observed to produce the greatest strength and optimum quality in the 359-type castings compared to aging at higher temperatures. The peak-strength for 359 alloy was observed to be attained after shorter aging times on condition that the aging temperature is increased. The aging times required for reaching peak-strength in 359 alloys are 32, 24, 1 h, 30, and 10 min when applying aging temperatures of 155, 170, 195, 220, and 245 °C, respectively. Aging treatment at higher temperatures is accompanied by a reduction in the tensile properties and quality index values of the castings; however, it also introduces the possibility of a significant economical strategy for minimizing the time and the cost of this treatment. Depending on the required level of tensile properties and based on the quality charts developed, it is possible to make a rigorous selection as to the most suitable aging parameters to be applied to the 359 alloy so as to obtain the best possible cost-effective compromise between alloy strength and quality.     

Synthesis and Magnetostriction of (CexTb1-x)0.5Pr0.5Fe2 Compounds

1. IntroductionBased on the single-ion model predictionl'], thecubic Laves phase compound PrFeZ possesses a gialltmagnetostrictive value due to its large second--orderStevens' factor ioJ, the ground state angular momentum J and the average radius squared < re, > ofthe 4f electron shell for the Pr3+ ion. And it is apotelltial candidate for giant magnetostrictive materials. However, previous researches showed that theradius of Prc+ ion is very large and the cubic PrFeZhas not been synthesiz…     

镍氢电池负极材料V2Ti0.5Cr0.5Ni1-xMox(x=0.02~0.08)的结构和电化学性能

为了改善镍氢电池负极材料的循环稳定性能, 采用真空感应电弧熔炼炉制备了V₂Ti_0.5Cr_0.5Ni_1-xMo_x (x=0.02~0.08)合金, 分析了不同含量的Mo替代Ni之后对合金电极的组织结构及电化学性能的影响。研究结果表明, 电极材料主要由BCC结构的V基固溶体主相和TiNi二次相组成, 随着合金中Mo替代Ni含量x由0.02增加到0.08, 合金电极的放电容量先增加后降低, 合金电极的循环稳定性能以及电化学动力学性能先得到改善而后降低, 合金电极的综合性能均在x=0.04时达到最好。     

Microstructure, mechanical properties and electrical conductivity of industrial Cu-0.5%Cr alloy processed by severe plastic deformation

Microstructure, mechanical properties and electrical conductivity of industrial Cu-0.5% alloy subjected to equal channel angular pressing (ECAP) by route A and cold rolling with and without aging treatment were investigated. The lamellar grains in thickness of 100 nm were obtained after eight ECAP passes. They were not further pancake shaped, but fragmentary and obtained less sharp boundaries with more dislocations in addition to cold rolling. After aging at 450 °C for 1 h, high density of dislocations and some coarse grains were observable after ECAP and the additional cold rolling, respectively. The tensile tests show that tensile strength arrived at 460 MPa and 484 MPa after four and eight passes of ECAP, respectively, the corresponding tensile strength increased to 570 MPa and 579 MPa after the additional cold rolling. However, the electrical conductivity was not more than 35% IACS. It was proved that four passes of ECAP followed by 90% cold rolling and aging at 450 °C for 1 h offered a short process for Cu-0.5%Cr alloy to balance the paradox of high strength and electrical conductivity, under which the tensile strength 554 MPa, elongation to failure 22% and electrical conductivity 84% of IACS could be obtained. The high strength was explained by precipitation strengthening and fine grain strengthening.     

Stress-induced shifting of the morphotropic phase boundary in sol-gel derived Pb(Zr0.5Ti0.5)O3 thin films

The structure evolution of Pb(Zr_0.5Ti_0.5)O₃ thin films with different thicknesses on the Pt(1 1 1)/Ti/SiO₂/Si substrates has been investigated using X-ray diffraction and Raman scattering. Differing from Pb(Zr_0.5Ti_0.5)O₃ bulk ceramic with a tetragonal phase, our results indicate that for PZT thin films with the same composition monoclinic phase with Cm space group coexisting with tetragonal phase can appear. It is suggested that tensile stress plays a role in shifting the morphotropic phase boundary to titanium-rich region in PZT thin films. The deteriorated ferroelectric properties of PZT thin films can be attributed mainly to the presence of thin non-ferroelectric layer and large tensile stress.     

Tribological Behavior of Al CoCrFeNi(Ti_(0.5)) High Entropy Alloys under Oil and MACs Lubrication

The tribological properties of AlCoCrFeNi and AlCoCrFeNiTi_(0.5) high entropy alloys under gear oil and multiply alkylated cyclopentanes(MACs)lubrication condition have been studied.The equiaxed crystal structure of AlCoCrFeNi alloy is obtained after heat-treatment.The AlCoCrFeNiTi_(0.5) alloy keeps dendrite structure.Under the gear oil with good lubrication action,AlCoCrFeNiTi_(0.5) alloy preserves better tribological properties than AlCoCrFeNi alloy.The delamination and crack behaviors tend to occur in the grain boundary of AlCoCrFeNi alloy and along the interdendrite region of AlCoCrFeNiTi_(0.5) alloy.Under the MACs with relatively poor lubrication action,the applied load slightly influences the wear behavior of AlCoCrFeNi alloy,but seriously impacts the wear mechanism of AlCoCrFeNiTi_(0.5) alloy.Compared with AlCoCrFeNi alloy,AlCoCrFeNiTi_(0.5) alloy keeps better wear-resistance at low applied load of 100 N,but preserves less wearresistance at high applied load of 200 N.     

Microstructure characterizations and strengthening mechanism of multi-principal component AlCoCrFeNiTi0.5 solid solution alloy with excellent mechanical properties

It was reported that AlCoCrFeNiTi_0.5 alloy exhibits excellent comprehensive mechanical properties. In this letter, this alloy was further studied on its microstructures and strengthening mechanism. The super-high strength and good plasticity of AlCoCrFeNiTi_0.5 alloy should be attributed to its microstructure of intrinsic strong body-centered cubic solid solution, and effective multiple strengthening mechanisms like solid solution strengthening, precipitation strengthening, and nano-composite strengthening effects, etc.