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镍基铸造高温合金是航空发动机与燃气轮机生产制造过程中应用的主要材料之一,在航空航天、能源工业、船舶舰艇等领域有着广泛的应用。现代航空工业的飞速发展离不开高温合金综合性能的快速提升,而热等静压技术在镍基铸造高温合金领域的应用对镍基铸造高温合金综合性能的改进方面发挥了举足轻重的作用。本文介绍了热等静压技术的工作原理与应用发展历史,总结了热等静压技术在镍基铸造高温合金领域的研究应用现状,重点阐述了热等静压技术对铸造高温合金的致密化作用机理与组织性能影响、热等静压对长期服役镍基铸造高温合金组织修复研究以及实现两种镍基高温合金扩散连接的应用优势与研究成果。同时指出热等静压技术研究中存在的一些问题及国内热等静压技术在镍基铸造高温合金领域的发展趋势。 相似文献
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铸造铝锂合金具有低密度、高模量、高比强度和比刚度等优点,适用于制备复杂薄壁构件,是航空航天、国防军工行业理想的结构材料。基于铸造铝锂合金的组织特征,探索提升合金强塑性的有效途径,可以夯实铸造铝锂合金在轻量化领域的优势地位,扩大其应用范围。首先,概括了国内外铸造铝锂合金的发展历程,归纳了铸造铝锂合金的组织特征与强韧化机制。然后,围绕铸造铝锂合金强韧化研究的最新进展,系统分析了合金化与热处理对铸造铝锂合金微观组织及力学性能的影响规律,总结了提升铸造铝锂合金强塑性的主要途径。最后,面向铸造铝锂合金实际工程需求,对其强韧化处理中尚存的科学难题与未来的研究方向进行了探讨与展望。 相似文献
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目前,新型轻质高温结构材料TiAl合金铸造部件已经进入工业化生产阶段,急需工业级铸造用TiAl母合金的制造技术和评估体系作为支撑。结合了钢铁研究总院铸造TiAl合金工程化研究和应用成果,概述了国内外铸造TiAl合金材料和部件的工程化应用现状,在此基础上,提出了铸造TiAl母合金的化学成分、规格等技术要求,并进一步对比分析了2次自耗熔炼、自耗熔炼+凝壳熔炼、自耗熔炼+凝壳熔炼+自耗熔炼等母合金制备工艺的优缺点,最后提出了工业级铸造TiAl母合金的技术发展方向。 相似文献
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稀土有色金属材料及其发展前景 总被引:5,自引:0,他引:5
本文系统地介绍了稀土金属或其化合物作为添加元素或合金成分在Al~-、Mg~-、Ti~-、Cu~-基合金及Ni~-、Co~-基超合金(不包括功能材料)中的作用、应用价值、应用开发现状及发展前景。指出推广稀土在铸造铝合金中的应用具有现实意义,开展合金相图、作用机理等基础研究,对开拓新的应用途径至关重要。 相似文献
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铸造稀土镁合金在我国航空工业中的应用 总被引:8,自引:1,他引:7
本文叙述了我国铸造稀土镁合金的分类、分成和性能;稀土在热强,高强耐热和高强合金中的应用,此外,简要介绍了铸造稀土镁合金在各种型号飞机,发动机,附件上的生产应用情况。 相似文献
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The effect of the volume fraction of I-phase on the hot compressive behavior and processing maps of the extruded Mg-Zn-Y alloys was examined, and the obtained results were compared with those of the cast alloys in a previous work. The average grain sizes, fractions of dynamically recrystallized (DRXed) grains, and sizes of DRXed grains of the extruded alloys after compressive deformation were significantly smaller, higher and smaller, respectively, than those of the cast alloys after compressive deformation under the same experimental conditions. This was because the microstructures of the extruded alloys, having much more grain boundaries and more refined I-phase particles than the cast alloys, provided a larger number of nucleation sites for dynamic recrystallization than those of the cast alloys. The constitutive equations for high-temperature deformation of the extruded and cast alloys could be derived using the same activation energy for plastic flow, which was close to the activation energy for lattice diffusion in magnesium. Compared with the cast alloys, the onset of the power law breakdown (PLB) occurred at larger Zener-Holloman (Z) parameter values in the extruded alloys. This was because the extruded alloys had finer initial grain sizes and higher fractions of finer DRXed grains compared to the cast alloys, such that the onset of PLB caused by creation of excessive concentrations of deformation-induced vacancies was delayed to a higher strain rate and a lower temperature. The flow-stress difference between the extruded alloys and the cast alloys could be attributed to the difference in the fraction of DRXed grains. According to the processing maps, the extruded alloys exhibited higher power dissipation efficiency and flow stability than the cast alloys. This agreed with the microstructural observations. 相似文献
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The Al–5.0 wt% Cu–0.6 wt% Mn alloys with different Fe contents were prepared by gravity die casting and squeeze casting. The difference in microstructures and mechanical properties of the T5 heat-treated alloys was examined by tensile test, optical microscopy, deep etching technique, scanning electron microscope and electron probe micro-analyzer. The results show that both β-Fe and α (CuFe) are observed in T5 heat-treated gravity die cast alloy and only α (CuFe) appears in the squeeze cast alloy when the Fe content is 0.5 wt%. When the Fe content is more than 1.0 wt%, the main Fe-rich intermetallics is α (CuFe) in both squeeze cast and gravity die cast alloys. The mechanical properties of both the gravity die cast and squeeze cast alloys decrease gradually with the increase of Fe content due to the decreased volume fraction of precipitation particles, the increased volume fraction of Fe-rich intermetallics and the increased size of α (Al) dendrites. The squeeze cast alloys with different Fe contents have superior mechanical properties compared to the gravity die cast alloys, which is mainly attributed to the reduction of porosity and refinement of Fe-rich intermetallics and α (Al) dendrite. In particularly, the elongation of the squeeze cast alloys is less sensitive to the Fe content than that of the gravity die cast alloys. An elongation level of 13.7% is obtained in squeeze cast alloy even when the Fe content is as high as 1.5%, while that of the gravity die cast alloy is only 5.3%. 相似文献
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Tensile strength,ductility and fracture of magnesium-silicon alloys 总被引:12,自引:0,他引:12
Tensile tests were performed between 293–573 K in order to investigate the mechanical properties of cast and extruded Mg-Si alloys. For the cast materials, Mg-high Si ( 10 wt%) alloys showed lower values of the highest tensile strength at temperatures up to 373 K, as compared to pure Mg and Mg-low Si (<10 wt%) alloys, whereas the strength at 573 K increased with increasing Si content. The addition of aluminum and zinc to the alloys was effective in increasing the strength. The fact that the Mg-high Si alloys showed lower strength than the Mg-low Si alloys was because a high volume of Mg2Si embrittled the Mg-Si alloys. Microstructural investigations revealed that the particles of Mg2Si were coarse for the cast materials and fracture of the particles was caused by deformation. The mechanical properties of the cast materials were improved by hot extrusion. Microstructural refinement by hot extrusion was responsible for the improvement of the mechanical properties. 相似文献
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《Materials & Design》2005,26(6):479-485
The tensile and fatigue properties of zinc–aluminum alloys (ZA-8, ZA-12 and ZA-27) in squeeze and gravity cast forms have been investigated. Tensile tests were conducted at ambient and elevated temperatures up to 150 °C. At low temperatures, the ultimate tensile strength and yielding strength of the squeeze cast alloys have been found to be superior those of the gravity-cast alloys, as the temperature increased they decreased. In the same way, Brinell hardness of the squeeze cast alloys were obtained at higher values than gravity castings. The fatigue tests were performed at a constant speed of 400 rev/min and under a number of stress levels ranging from 100 to 150 MPa. The fatigue behaviour results of the ZA alloys were similar to obtained from the tensile testing. The squeeze cast alloys exhibited good fatigue resistance in proportion to the gravity castings. Metallography examinations showed that the microstructure of the castings differed according to the method of casting used. It was considered that the mechanical properties of the alloys were affected from these micro-structural changes. 相似文献
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Cong Li Jian Chen Wei Li Yongle Hu Yanjie Ren Wei Qiu Jianjun He Jianlin Chen 《Materials Science-Poland》2014,32(3):341-349
Microstructures and mechanical properties of Cu-35Ni-15Al alloy in cast and porous states were studied by scanning electron microscopy and compression tests. The influence of porosity, deformation temperature and loading rate on mechanical properties of the two kinds of alloys was investigated. The results show that the as cast alloy and porous alloys have almost the same phase constitution: Cu rich phase, Ni rich phase and K intermetallics. The yield strength of porous alloys increases continuously with decreasing porosity, the relationship between porosity and yield stress follows Gibson-Ashby equation. With decreasing deformation temperature, the yield strength of as cast alloy and porous alloy increase. With the increase of loading rate, the yield strength of these alloys shows an increasing trend. After compression, the microstructure of as cast alloy is more uniform, and porous alloys are more prone to have localized deformations. 相似文献
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M. Van Rooyen P. F. Colijn Th. H. De Keijser E. J. Mittemeijer 《Journal of Materials Science》1986,21(7):2373-2384
Rapidly solidified aluminium, AlMg (0 to 16.5 at % Mg) and AlSi (0 to 20.2 at % Si) alloys were produced by melt spinning. The AlMg ribbons were single-phase, whereas the AlSi ribbons were dual-phase. In the ribbons of both alloy systems the fineness of the microstructure increased with increasing alloying element content. The melt-spun ribbons were consolidated by hot extrusion. For comparison, conventionally cast alloys of corresponding compositions were extruded analogously. During the extrusion process in AlMg (16.5 at % Mg) and in the AlSi alloys precipitation occurred. The consolidation of the ribbons was markedly influenced by the oxide layer on the ribbon surfaces: in the AlSi consolidates a more intimate contact between the ribbons was apparent than in the aluminium and AlMg consolidates. In the extrudates of the conventionally cast alloys the grains and second-phase particles were much larger than in the consolidates. The observed dependence on alloy composition of hardness, ultimate tensile strength and elongation at fracture of both consolidated ribbons and extrudates of the conventionally cast alloys are discussed in terms of matrix grain size, solute content of the matrix, amount and size of second-phase particles and recrystallization behaviour. For all compositions of the alloys the Vickers hardness of the as-melt-spun ribbons was higher than that of the consolidated products, owing to recrystallization and precipitation provoked by the hot consolidation process. The ultimate tensile strength as well as the elongation at fracture of both consolidated ribbons and extruded conventionally cast alloys did not differ significantly for AlMg. However, due to a finer microstructure and a stronger inter-ribbon bonding, for AlSi alloys with a high silicon content the rapid solidification processing route did yield a product with significantly improved mechanical properties as compared with the extruded conventionally cast alloys. 相似文献
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V. N. Khodorenko V. É. Gyunter A. N. Monogenov Yu. F. Yasenchuk 《Technical Physics Letters》2001,27(11):970-972
It was found that the phase transitions in porous titanium-nickel alloys are characterized by an extended temperature interval of heat release (on cooling) and heat absorption (on heating). The total heat released and absorbed in porous titanium-nickel alloys markedly exceeds that in the analogous cast alloys. The maximum exothermal and endothermal effects are manifested in the alloys with fine pores. The extended temperature interval and increased amount of released and absorbed heat during the phase transitions in porous TiNi alloys, as compared to the analogous cast alloys, is determined by the degree of porosity, the character of inhomogeneity of the porous alloy structure, and the width of the martensite transformation interval. 相似文献
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Jin-Yoo Suh Young-Su LeeJae-Hyeok Shim Hoon Mo Park 《Computational Materials Science》2012,51(1):365-371
A methodology is proposed for predicting the elastic properties of precipitation-hardened alloys by combining different modeling techniques: the CALPHAD method, first-principles calculation, and elasticity models. The proposed procedure was applied to conventional aluminum cast alloys to predict their elastic moduli. The predicted Young’s moduli are in reasonable agreement with values reported in the literature, which verifies the potential applicability of the methodology to the development of high-stiffness aluminum cast alloys. 相似文献