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Effect of intergranular β phase on the rupture plasticity of the low expansion Inconel 783 superalloy

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Baosteel Technical Research 2011年第4期5卷 16-20页

作者： WEI Zhigang ZHAO Yating XIE Wei CHEN Guosheng Special Steel Technology Center Research Institute Baoshan Iron ＆ Steel Co. Ltd. Shanghai 200940 China Special Steel Business Unit Baoshan Iron ＆ Steel Co. Ltd. Shanghai 200940 China

High temperature rupture specimens with different rapture plasticity are investigated. The rupture fracture failure of Inconel 783 superalloy is researched by analyzing the fracture surface and microstructure of the rupture specimens. The intergranular β phase precipitated sufficiently with favorable morphology can efficiently strengthen grain boundaries that can achieve a full plastic deformation of grains. Additionally, the intergranular β phase can effectively restrain the occurrence and expansion of intergranular cracks during the rupture test. The intergranular β phase insufficiently precipitated can weaken the intergranular cohesion and lead to the occurrence and expansion of cracks; thus, the grains cannot be fully deformed before breaking. Therefore, the β phase precipitated in the grain boundaries can significantly increase the rupture plasticity of Inconel 783 superalloy.

关键词： Inconel 783 superalloy β phase rupture plasticity

Solidification structures of high niobium containing TiAl alloys

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Journal of University of Science and Technology Beijing 2005年第2期12卷 134-138页

作者： JingwenXu JunpinLin YanliWang ZhiLin GuoliangChen StateKeyLaboratoryforAdvancedMetalsandMaterials UniversityofScienceandTechnologyBeijing100083China

To understand the effect of alloy stoichiometry on the microstructural development and mechanical behavior of γ-TiAl- based materials, it is necessary to have a determination of the phase relationships for the TiAl alloy system near the γ phase field. Cast structures and phases of Ti-(43-47)Al-8Nb-(1-2)Mn (at%) alloys have been studied by using scanning electron microscope and X-ray diffraction. Their solidification path and microstructure development during the solidification were analyzed. The experimental results show that the alloys with different Al contents form different macrostructures and microstructural morphologies. This indi- cates that the solidification paths are different with different Al contents. The alloy with 43Al forms equiaxed grain structure, and the solidification path is as follows: L —? L+β —? β —? α+β —> α+β cores —> O2+γ+B2 cores. Whereas the alloy with 47Al forms colum- nar grain structure, and the solidification path is as follows: L —> L+β —? α+β+L —? α+γ+β cores —> tXj+γ+BZ cores. The p phase is their primary solid phase and can be retained to ambient temperature. The alloy with 43Al solidifies completely into β phase. The peritectic reactions L+P —> α and L+α-? γ appear when the Al content increases to 47Al.

关键词： high niobium titanium aluminides microstructure phase transformation β phase

Aging Behaviors of W-Ni-Fe Ternary Alloys with High Ni-to-Fe Ratios

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Journal of Materials Science & Technology 2003年第6期19卷 631-633页

作者： Ronghua LI, Jihua HUANG, Sheng YIN and Jun ZHAOSchool of Materials Science & Engineering, University of Science & Technology Beijing, Beijing 100083, China Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The hardness variation of two kinds of alloys with 36 wt pct W content and 7/3, 9/1 Ni-to-Fe ratios during strain aging at 800℃ was studied. The microstructures of the aged alloys were analyzed by X-ray diffraction and TEM. The results show that the strain aging hardness of W-Ni-Fe ternary alloy with 7/3 Ni-to-Fe ratio decreases monotonically with the increase of aging time. Under the same conditions, the hardness of 9/1 Ni-to-Fe ratio alloy decreases in the initial aging stage, but then increases as aging process goes on. X ray diffraction and TEM analysis show that there is not any precipitation depositing from the alloy with 7/3 Ni-to-Fe ratio during aging. The monotonic decrease in hardness of this alloy during aging process results from the recovery, recrystallization and solid solubility declining. In the alloy of 9/1 Ni-to-Fe ratio, the fine β phase precipitates dispersively during aging which hardens the alloy. The two different kinds of mechanisms (the softening one and the hardening one) decide the hardness variation of the alloy with 9/1 Ni-to-Fe ratio mentioned above.

关键词： W-Ni-Fe Tungsten heavy alloys Ni-to-Fe ratio Strain aging β phase

Effect of Fe and Mo additions on microstructure and mechanical properties of TiAl intermetallics

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Transactions of Nonferrous Metals Society of China 2012年第3期22卷 521-527页

作者：邱从章刘咏黄岚张伟刘彬卢斌中南大学粉末冶金国家重点实验室长沙410083

The ductility of TiAl intermetallics can be improved through stabilizing the ductile β *** β-stabilized Ti-45Al-xFe-yMo（x,y=1,2,3,4） alloys were designed through adding the β stabilizing elements Fe and *** microstructural evolution and deformation behavior of the Ti-45Al-xFe-yMo alloys were *** results show that the amount of β（B2） phase is increased with the increase of alloying *** shows a higher capability for stabilizing the β phase than *** the optimized Ti-45Al-3Fe-2Mo alloy,the grains are significantly refined to about 12 μm,and this alloy shows a very good hot ductility at the elevated temperature.

关键词： TiAl intermetallics Fe Mo β phase grain refinement

Self tempering effect of near eutectic Al-Si casting with different wall thickness solidified and cooled in permanent die

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Transactions of Nonferrous Metals Society of China 2011年第12期21卷 2576-2583页

作者：胡心平谢玲张娟山东轻工业学院机械工程学院济南250353 山东省轻工装备先进制造与测控技术重点实验室济南250353

In order to study the self tempering effect on the solidification of Al-Si alloy, a setup was designed to conduct experiments. The characters of β phases in different thicknesses of Al-Si samples were investigated. The results show that the size distributions of β phases obey the logarithmic normal distribution. The Brinell hardness tests were also carried out. The tested hardness results show that the hardness distribution of the casting cooled in water is evener than that cooled in air, and its averaged value is higher than that cooled in air.

关键词： β phase Al-Si alloy self tempering effect Brinell hardness

Influence of Mo content on microstructure and mechanical properties of β-containing TiAl alloy

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Transactions of Nonferrous Metals Society of China 2017年第4期27卷 820-828页

作者： Wen-chen XU Kai HUANG Shi-feng WU Ying-ying ZONG De-bin SHAN School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China

The influence of Mo content on the microstructure and mechanical properties of the Ti?45Al?5Nb?xMo?0.3Y(x=0.6,0.8,1.0,1.2)alloys was studied using small ingots produced by non-consumable electrode argon arc *** results show that smallquantities ofβphase are distributed alongγ/α2lamellar colony boundaries as discontinuous network in the TiAl alloys owing to thesegregation of Mo ***γphase forms in the interdentritic microsegregation area when the Mo addition exceeds0.8%.Theβandγphases can be eliminated effectively by subsequent homogenization heat treatment at the temperature above Tα.The evolutionof the strength,microhardness and ductility at different Mo contents under as-cast and as-homogenization treated conditions wasanalyzed,indicating that excessive Mo addition is prone to cause the microsegregation,thus decreasing the strength andmicrohardness obviously,which can be improved effectively by subsequent homogenization heat treatment.

关键词： TiAl alloy β phase microstructure mechanical properties homogenization treatment