共查询到10条相似文献,搜索用时 109 毫秒
1.
LIU Yang WANG Lei WANG Shuai CUI Tong 《材料与冶金学报》2006,5(4):288-291,299
With the rapid development of the aero-spaceindustry, the more excellent properties of the superal-loy used for turbine disk are required. GH4586 alloyis a new precipitation hardening Ni-base wrought su-peralloy which is developed independently in Chi-na[1,2]. GH4586 alloy has improved impact toughnessat RT(room temperature), high temperature stressrupture and creep properties with higher cleanlinessand it has already been applied on the turbine disk ofrocket with 120 Thigh driving force suc… 相似文献
2.
3.
K. P. Rao S. M. Doraivelu H. Md. Roshan Y. V. R. K. Prasad 《Metallurgical and Materials Transactions A》1983,14(8):1671-1679
Al-5 wt pct Si alloy is processed by upset forging in the temperature range 300 K to 800 K and in the strain rate range 0.02
to 200 s−1. The hardness and tensile properties of the product have been studied. A “safe” window in the strain rate-temperature field
has been identified for processing of this alloy to obtain maximum tensile ductility in the product. For the above strain
rate range, the temperature range of processing is 550 K to 700 K for obtaining high ductility in the product. On the basis
of microstructure and the ductility of the product, the temperature-strain rate regimes of damage due to cavity formation
at particles and wedge cracking have been isolated for this alloy. The tensile fracture features recorded on the product specimens
are in conformity with the above damage mechanisms. A high temperature treatment above ≈600 K followed by fairly fast cooling
gives solid solution strengthening in the alloy at room temperature.
Formerly Assistant Professor, Indian Institute of Technology, Madras, is now Visiting Scientist (AFWAL Materials Laboratory),
Universal Energy Systems Inc., Dayton, OH 45432. 相似文献
4.
5.
《钢铁研究学报(英文版)》2016,(9):963-972
Room temperature tensile tests of Fe-Mn-Al-C low density steels with four different chemical compositions were conducted to clarify the dominant deformation mechanisms.Parameters like product of strength and elongation,as well as specific strength and curves of stress-strain relations were calculated.The microstructures and tensile fracture morphologies were observed by optical microscope,scanning electron microscope and transmission electron microscope.The tensile behavior of low density steel was correlated to the microstructural evolution during plastic deformation,and the effects of elements,cooling process and heat treatment temperature on the mechanical properties of the steels were analyzed.The results show that the tensile strength of steels with different cooling modes is more than 1 000 MPa.The highest tensile strength of 28Mn-12Al alloy reached 1 230 MPa,with corresponding specific strength of 189.16 MPa·cm~3·g~(-1),while the specific strength of 28Mn-10 Al alloy was 178.98 MPa·cm~3·g~(-1),and the excellent product of strength and elongation of 28Mn-8Al alloy was over 69.2 GPa·%.A large number of ferrite reduced the ductility and strain hardening rate of the alloy,while the existence of κ carbides may improve the strength but weaken the plasticity.Some fine κ carbides appeared in the water-quenched specimen,while coarse κ carbides were observed in the air-cooled specimen.High temperature heat treatment improved the decomposition kinetics of γ phase and the diffusion rate of carbon,thus speeded up the precipitation of fine κ carbides.The dominant deformation mechanism of low density steel was planar glide,including shear-band-induced plasticity and microbandinduced plasticity. 相似文献
6.
Ti-62A合金是一种新型高强高韧损伤容限型钛合金,研究了固溶温度对Ti-62A合金30 mm厚板材的显微组织、拉伸性能以及断裂韧性的影响规律。研究结果表明:Ti-62A合金Φ720 mm铸锭经单相区和两相区多道次大变形轧制后所得的30 mm厚板材组织为典型的片层组织,由片层状的α相和β转变组织构成,组织均匀,片层状α相平均宽度约为2.5μm,长度在40~65μm之间。两相区固溶+时效处理后,合金的组织类型为片层状组织,即片层状的初生α相(αp)相与β转变组织,随固溶温度升高,合金中的初生α相(αp)相含量显著减少,β转变组织逐渐增多,次生α相(αs)片层宽度增大,同时合金的强度下降,塑性上升,当接近相变点时这种趋势变缓。单相区固溶+时效处理获得魏氏组织,晶粒粗大,晶界平直而清晰,其拉伸强度高于920℃和940℃固溶时的片层组织,但塑性显著降低;与900℃固溶时相比强度和塑性均降低。合金的断裂韧性随固溶温度的上升而逐渐升高,单相区固溶并时效后的魏氏组织的断裂韧性明显优于两相区固溶并时效后的片层组织。 相似文献
7.
Douglas M. Symons Anthony W. Thompson 《Metallurgical and Materials Transactions A》1996,27(1):101-110
The effect of hydrogen on the fracture of a nickel-base superalloy, alloy X-750, was investigated in the HTH condition. The
effect of hydrogen was examined through tensile testing incorporating observations from scanning electron microscopy and light
microscopy. The ductility at 25 °C, as measured by elongation to failure for tensile specimens, was reduced from 21 pct for
noncharged specimens to 7.3 pct for 5.7 ppm hydrogen and to 3.5 pct for 65 ppm hydrogen. The elongation to failure was a function
of the strain rate and test temperature. For hydrogen-charged specimens, the elongation decreased as the strain rate decreased
at a constant temperature, while for a constant strain rate and varying temperature, there was a maximum in embrittlement
near 25 °C and no embrittlement at -196 °C. For the noncharged specimens, the elongation monotonically increased as temperature
increased, while there was no noticeable effect of strain rate. Prestraining prior to charging dramatically decreased elongation
after hydrogen charging. When the strain rate was increased on the prestrained specimens, more plastic deformation was observed
prior to failure. Failure did not occur until the flow stress was reached, supporting the proposition that plasticity is required
for failure. The intergranular failure mechanism in alloy X-750 was a microvoid initiation process at grain boundary carbides
followed by void growth and coalescence. The void initiation strain, as determined from tensile data and from sectioning unfractured
specimens, was observed to be much lower in the hydrogen-charged specimens as compared to noncharged specimens. The reduced
ductility may be explained by either a reduction of the interfacial strength of the carbide-matrix interface or a local hydrogen
pressure at the carbide-matrix interface. 相似文献
8.
Md. Zafir Alam N. Hazari Vijay K. Varma Dipak K. Das 《Metallurgical and Materials Transactions A》2011,42(13):4064-4074
The tensile behavior of a directionally solidified (DS) Ni-base superalloy, namely, CM-247LC, was evaluated in the presence
of a Pt-aluminide bond coat. The effect of the thermal cycling exposure of the coated alloy at 1373 K (1100 °C) on its tensile
properties was examined. The tensile properties were evaluated at a temperature of 1143 K (870 °C). The presence of the bond
coating caused an approximately 8 pct drop in the strength of the alloy in the as-coated condition. However, the coating did
not appreciably affect the tensile ductility of the substrate alloy. The bond coat prevented oxidation-related surface damage
to the superalloy during thermal cycling exposure in air at 1373 K (1100 °C). Such cyclic oxidation exposure (up to 750 hours)
did not cause any further reduction in yield strength (YS) of the coated alloy. There was a marginal decrease in the ultimate
tensile strength (UTS) with increased exposure duration. Because of the oxidation protection provided by the bond coat, the
drastic loss in ductility of the alloy, which would have happened in the absence of the coating, was prevented. 相似文献
9.