Anomalous yield and intermediate temperature brittleness behaviors of directionally solidified nickel-based superalloy

Sheng, Li Yuan; Yang, Fang; Jianting, Guo; Xi, Tao

doi:10.1016/s1003-6326(14)63110-1

Cited by 49 publications

(21 citation statements)

References 27 publications

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“…The fine Ni3Al grain, trace B addition, Al2O3 dispersoids and massive crystal defects all contribute to the mechanical properties. According the previous researches [8,14,31,32], the trace B addition in the Ni3Al alloy with 24 % (at.%) Al increased the ductility obviously by improving the cohesion of grain boundary. In the present research, though trace B is added in the Ni3Al alloy, however the milling and thermal explosion would preserve the B in the grain [12,33,34].…”

Section: Mechanical Propertiesmentioning

confidence: 87%

Characterization of Ni3Al Alloy Fabricated by Thermal Explosion and Hot Extrusion Process

Sheng¹,

Du²,

Zan³

et al. 2018

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In the present paper, the trace B doped Ni3Al alloy was prepared by the thermal explosion and hot extrusion (TH/HE) technique. Its microstructure characterization and mechanical properties were carried out by OM, XRD, TEM, compression and microhardness tests. Microstructure examinations exhibit that the TH/HE technology has transformed the powders into Ni3Al alloy with less porosity. In the synthesized part, coarse and ultrafine Ni3Al grains constitute the dual-scale grain structure with segregated Al2O3 particles along grain boundary. TEM observations reveal that γ-Ni, Al2O3 and Ni3Al phases coexist in the synthesized part. Moreover, the Al2O3 particles in the synthesized part have α-Al2O3 and γ-Al2O3 two crystal structures. In addition, there is a transition region along the interface of Al2O3 and Ni3Al grain. The subsequent hot extrusion optimizes the microstructure of the extruded part by homogenizing the Ni3Al grain, uniformly distributing Al2O3 and generating massive substructures. The great deformation results in the pileup of dislocations, intersected dislocations and substructures. Moreover, the movement of dislocation promotes the formation of micro-twinning in the Ni3Al grain, which is accompanied with the stacking faults and nano-structure. The mechanical properties exhibit that the microstructure optimization caused by the TE/HE technique improves the compressive ductility and strength of the Ni3Al alloy obviously.

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Section: Mechanical Propertiesmentioning

confidence: 87%

Characterization of Ni3Al Alloy Fabricated by Thermal Explosion and Hot Extrusion Process

Sheng¹,

Du²,

Zan³

et al. 2018

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“…Based on the lattice parameters of Mg 3 Zn 2 Y 3 phase and α-Mg phase, there would be great difference between these phase. Moreover, the Mg 3 Zn 2 Y 3 /α-Mg eutectic structure is the final solidification region, which would result in great element segregation and increase the crystal misfit along phase interface [29][30][31]. Due to the detrimental effect of the coarse strengthening phase, the heat treatment is carried out to solid solute them.…”

Section: Resultsmentioning

confidence: 99%

“…But the mechanical properties of Mg-Zn alloy is not high enough, because of the low proportion of strengthening precipitate and coarse grain [16,17]. Previous researches [18,19] exhibit that the rare earth could increase the strength of the alloy by enhancing grain boundary. The Cheng et al studied the minor Y doped Mg alloy and exhibited that the minor Y addition could increase the impact toughness more than one times by changing the deformation mode from twinning to dislocation slip [20].…”

Section: Introductionmentioning

confidence: 99%

Influence of heat treatment and hot extrusion on the microstructure and tensile properties of rare earth modified Mg-Zn based alloy

Sheng

Wang

et al. 2018

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. In the present paper, the Mg-Zn-Y-Nd alloy was prepared by casting, heat treatment and hot extrusion. The microstructure and mechanical properties of the alloys were tested by OM, SEM, TEM and tensile test. The results showed that the Mg 3 Zn 2 Y 3 phase is the main strengthening phase and forms the eutectic structure with α-Mg matrix in the as cast alloy. The strengthening phases semi-continuously connect and separate the α-Mg matrix into cell structure. The average grain size of the as cast alloy is about 60 μm. The heat treatment promotes the solid solution of the strengthening phase and precipitation of small particles inside grain.Compared with the as cast alloy, the heat treatment increases grain size a little and mechanical properties more than 30%. The hot extrusion refines the grain and strengthening phase, which increase the mechanical properties significantly. Moreover, the great deformation by the hot extrusion results in the ultrafine structure and abundant of crystal defects. The intersection of micro-twins lead to the special region with nanometer size. IntroductionMagnesium (Mg) alloys have attracted great attention as the light weight structural materials owing to their high specific strength, low density, ease of recycling and good damping, which can be applied in many fields, including implants, hand tools, sports equipment, automobiles, aerospace applications and electronic equipment [1][2][3][4]. Moreover, the recent research exhibited that the clinic trial of coronary stent made by rare earth doped Mg alloy exhibited good therapeutic effect without thrombosis, which demonstrated the good application prospect of Mg based implant [5]. However, the hexagonal closepacked (HCP) crystal structure of Mg limited the number of initiation slip systems during deformation at relative low temperature, which resulted in the poor deformability of Mg alloy [6]. The poor ductility and low strength of Mg alloy handicapped its wide application. To conquer these shortcomings of Mg alloy, many methods had been applied [7][8][9]. Alloying and thermal processing had been thought as the efficient method to improve the mechanical properties of Mg alloy at room and high temperature.Recently, the investigations [10-12] on biomedical magnesium alloys revealed that the addition of Zn could improve its mechanical properties and corrosion resistance with little influence on its biocompatibility, because the Zn is the essential element of the human body. Then a series of new magnesium alloys for biomedical application were developed [13][14][15]. The research of Zhang et al. [10] exhibited that Zn addition in Mg could increases the mechanical performance and biocompatibility, and the Mg-6Zn (wt.%) alloy was the best choice. But the mechanical properties of Mg-Zn alloy is not

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“…This property has attracted much attention for high temperature applications. For example, due to this property, L1 2 γ Ni-base superalloys are widely used for blades and vanes in gas turbine engines for aircrafts and power generations [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effects of Alloying Atoms on Antiphase Boundary Energy and Yield Stress Anomaly of L12 Intermetallics: First-Principles Study

Gao

Wang

et al. 2018

Crystals

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Abstract:The antiphase boundary energies of {111} and {010} planes in L1 2 intermetallics (Ni 3 Ge, Ni 3 Si, Al 3 Sc, Ni 3 Al, Ni 3 Ga and Al 3 Ti) under different pressure are presented using first-principle methods. The yield stress anomaly is predicted by the energy criterion p-factor based on the anisotropy of antiphase boundary energies and elasticity. These L1 2 intermetallics exhibit anomalous yield stress behavior except Al 3 Sc. It is found that pressure cannot introduce the transition between anomalous and normal behavior. In order to investigate the transition, Al 3 Sc, Ni 3 Si and Ni 3 Ge with substituting atoms are investigated in detail due to p-factors of them are close to the critical value p c = √ 3. Al 3 Sc can change to anomalous when Sc atoms in {010} planes are substituted by Ti with plane concentration 25%. When Li substitutes Al in {111} planes, anomalous Al 3 Sc will change to normal. Ni 3 Si and Ni 3 Ge can exhibit normal yield stress behavior when Ge and Si in {111} planes are substituted by alloying atoms with plane concentrations 12.5% and 25%. When Ga and Al substitute in {010} planes, normal Ni 3 Si and Ni 3 Ge will revert to anomalous behavior. Therefore, transparent transition between normal and anomalous yield stress behavior in L1 2 intermetallics can be introduced by alloying atoms.

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Anomalous yield and intermediate temperature brittleness behaviors of directionally solidified nickel-based superalloy

Cited by 49 publications

References 27 publications

Characterization of Ni3Al Alloy Fabricated by Thermal Explosion and Hot Extrusion Process

Characterization of Ni3Al Alloy Fabricated by Thermal Explosion and Hot Extrusion Process

Influence of heat treatment and hot extrusion on the microstructure and tensile properties of rare earth modified Mg-Zn based alloy

Effects of Alloying Atoms on Antiphase Boundary Energy and Yield Stress Anomaly of L12 Intermetallics: First-Principles Study

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