Intergranular Fracture in Neutron Irradiated Vanadium-20 Wt.% Titanium Alloys Undoped and Doped with Phosphorus

1996 ◽  
Vol 458 ◽  
Author(s):  
J. Kameda ◽  
T. E. Bloomer ◽  
D. Y. Lyu
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Neutron Irradiation ◽  
Intergranular Fracture ◽  
Mixed Mode ◽  
Fracture Behavior ◽  
Testing Method ◽  
Ti Alloys ◽  
Microcrack Formation ◽  
Heterogeneous Formation

ABSTRACTThis paper presents the effect of neutron irradiation (9.8 × 1024 n/m2 at 438 °C) on the mechanical properties in V-20 wt.% Ti alloys undoped and doped with P using a small punch testing method. The same amount of neutron irradiation-induced hardening, that is almost temperature independent, was observed in undoped and P doped alloys. Neutron irradiation facilitated heterogeneous formation of grain boundary microcracks, not leading to specimen failure, in the undoped alloy. An irradiated undoped alloy showed ductility loss, that is not as much as expected from the easy microcrack formation due to a mixed mode of intergranular and transgranular cracking. Conversely, in the P doped alloy, intergranular microcracking was suppressed and low temperature ductility was improved by the irradiation. The intergranular fracture behavior controlling the ductility change is discussed in terms of the grain boundary composition and yield strength affected by the neutron irradiation.

Grain-Boundary Segregation of Phosphorus and Inter-Granular Fracture Behavior under Low Tensile Stresses

2012 ◽  
Vol 525-526 ◽  
pp. 273-276 ◽  
Author(s):  
Yu Dong Fu ◽  
Qing Fen Li ◽  
Wei Xin Sun
Keyword(s):  
Grain Boundary ◽  
Intergranular Fracture ◽  
Fracture Behavior ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Fracture Rate ◽  
Phosphorus Segregation ◽  
Tensile Stresses ◽  
Segregation Behavior ◽  
Segregation Level

The present work is an effort to provide experimental results focusing on segregation behavior of phosphorus at grain boundary and the intergranular fracture behavio under low tensile stresses. AES (Auger electron spectroscopy) experiments and dynamic analyses on the non-equilibrium grain-boundary segregation (NGS) of phosphorus and the SEM photos of intergranular fracture in Auger specimens in 12Cr1MoV steel were carried out in this paper. The variation of phosphorus segregation level in grain boundary under different low tensile stresses and at different temperature were obtained. Results show that NGS of phosphorus occurred in the experimental steel while subjected to low tensile stresses. Maximum values of phosphorus segregation level were obtained at the critical times. SEM photos of intergranular fracture in Auger specimens of the test steel show that the intergranular fracture rate increased with increasing concentration of phosphorus. The intergranular fracture behavior is accordant with the segregation behavior of phosphorus at grain boundary.

Formation of Grain Boundary α in β Ti Alloys: Its Role in Deformation and Fracture Behavior of These Alloys

2010 ◽  
Vol 42 (3) ◽  
pp. 645-650 ◽  
Author(s):  
John W. Foltz ◽  
Brian Welk ◽  
Peter C. Collins ◽  
Hamish L. Fraser ◽  
James C. Williams
Keyword(s):  
Grain Boundary ◽  
Fracture Behavior ◽  
Ti Alloys ◽  
Deformation And Fracture

Comparative Study on Intergranular Segregation of Sulfur and Phosphorus Induced During Neutron Irradiation And Thermal Ageing in Vanadium-20 WT.% Titanium Alloys

1996 ◽  
Vol 439 ◽  
Author(s):  
T. E. Bloomer ◽  
D. Y. Lyu ◽  
J. Kameda
Keyword(s):  
Grain Boundary ◽  
Comparative Study ◽  
Titanium Alloys ◽  
Neutron Irradiation ◽  
Dynamic Interaction ◽  
Thermal Ageing ◽  
Vanadium Alloys ◽  
Impurity Segregation ◽  
Ti Alloys ◽  
Underlying Mechanisms

AbstractIntergranular impurity segregation induced during neutron irradiation (9.8 × 1024 n/mr at 438 °C) and thermal ageing has been studied in V-20 wt.% Ti alloys undoped, P doped and S doped all containing residual C and O. Neutron irradiation induced intergranular segregation and desegregation of S in undoped and S doped alloys, respectively. Thermal ageing resulted in a large increase in the S segregation in the undoped and S doped alloys. However, all unirradiated, aged and irradiated P doped alloys showed negligible S segregation. The vanadium alloys had smaller P segregation, compared to the S segregation in the undoped and S doped alloys. The irradiation and ageing enhanced the P segregation in a different fashion depending on the alloys. The grain boundary enrichment of C, O and Ti was reduced during the irradiation but promoted by the thermal ageing. The underlying mechanisms controlling intergranular impurity segregation caused by irradiation or thermal ageing are discussed in light of the impurity solubility change and dynamic interaction of defect and impurity fluxes.

Design of Li2 -Type Ni3 Si Intermetallics

1990 ◽  
Vol 186 ◽  
Author(s):  
T. Takasugi ◽  
O. Izumi
Keyword(s):  
Mechanical Properties ◽  
Environmental Effect ◽  
Fracture Behavior ◽  
Elevated Temperatures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ambient Temperatures ◽  
Ti Alloys ◽  
Ti Content ◽  
Effect Test

AbstractBased on the alloying method to improve the intergranular cohesion of LI2 alloys, it was shown that the Ni3 Si alloy was ductilized by the addition of Ti element and the control of stoicliometry. Metallographic and structural observations in the alloys along Ni3Si-Ni 3 Ti section were performed on optical microscopy, X-ray diffraction, TEM and ALCHEMI. It was shown that Ti element with a solubility of about 11 at.% substituted for the Si sites and the Ni3 (Si,Ti) alloys were highly ordered. The mechanical properties and fracture behavior of Ni3 (Si,Ti) polycrystals were investigated in terms of composition, the environmental effect, test temperature and the doping of B, C and Be. At ambient temperatures, higher ductility accompanied by a high portion of transgranular fractures was observed in the alloys with higher Ti and Ni contents, doped with B and C, and tested in vacuum. Hydrogen and oxygen from environment strongly affected the ductility and fracture of these alloys at ambient and elevated temperatures, respectively. The yield stress increased with increasing Ti content.

Microstructures after Bending Deformations to Fracture of Zr Ion Irradiated Superplastic Ceramic 3Y-TZP

2007 ◽  
Vol 551-552 ◽  
pp. 475-480
Author(s):  
Takaaki Sakuma ◽  
Yoshinobu Motohashi ◽  
Taiju Shibata ◽  
Kazuhiro Sawa ◽  
Masahiro Ishihara
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Intergranular Fracture ◽  
Ion Irradiation ◽  
Tetragonal Zirconia ◽  
Surface Region ◽  
Tandem Accelerator ◽  
Tetragonal Zirconia Polycrystal

The effects of Zr ion irradiation on the mechanical properties of a typical superplastic ceramic, 3mol% yttria stabilized tetragonal zirconia polycrystal (3Y-TZP), were examined and discussed. The specimens were irradiated by Zr11+ ions with 130MeV at fluence level of 3.5×1012 and 2.1×1013 ions/cm2 in the TANDEM accelerator at Tokai Reasearch Establishment of JAEA. Microstructures after annealing and bending deformations to fracture of Zr ion irradiated 3Y-TZP were examined. It was found that the ratio of intergranular fracture to intragranular fracture was increased in the region that was affected by Zr ion irradiation. It seemed that grain boundary cohesion became relatively weak in the irradiated surface region. The influence of Zr ion irradiation on the mechanical properties almost disappeared when the irradiated 3Y-TZP was subsequently heated to 1173K.

Integranular Fracture: The Effect of Grain Boundary Orientation and Crack Growth Directions

1999 ◽  
Vol 586 ◽  
Author(s):  
Jeffrey W. Kysar
Keyword(s):  
Grain Boundary ◽  
Single Crystal ◽  
Intergranular Fracture ◽  
Cohesive Zone ◽  
Fracture Behavior ◽  
Cohesive Zone Model ◽  
Boundary Energy ◽  
Zone Model ◽  
Directional Dependence ◽  
Symmetric Tilt

ABSTRACTIntergranular fracture is a common failure mechanism for which many issues remain to be resolved. In this study we investigate intergranular fracture behavior of specially oriented symmetric tilt bicrystals of aluminum as well as the fracture behavior of a crack along the interface of a copper-sapphire bicrystal. We begin by describing briefly the structure of a symmetric tilt grain boundary which leads to a discussion of the types of issues related to intergranular fracture that can be addressed with symmetric tilt grain boundaries. We then discuss in detail one of these issues, that of the directional dependence of fracture, and present results of finite element simulations of a copper-sapphire bicrystal specimen that exhibits the directional dependence of fracture. The simulations account for the single crystal nature of the constituents and use a cohesive-zone model, for which the grain boundary energy can be varied, to simulate the fracture process along the interface. The directional dependence of fracture emerges from the simulations for a broad range of parameters in the constitutive models of both the single crystal constituents as well as the interfacial cohesive-zone.

Investigation of mechanical and fracture behavior of pure and carbon fiber reinforced ABS samples processed by fused filament fabrication process

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cem Boğa
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
3D Printing ◽  
Mixed Mode ◽  
Fracture Behavior ◽  
Production Method ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Printing Technique ◽  
3D Printing Technique

Purpose Acrylonitrile butadiene styrene (ABS), as a light and high strength thermoplastic polymer, has found extensive applications in different industries. Fused filament fabrication, known as three-dimensional (3D) printing technique is considered a rapid prototyping technique that is frequently applied for production of samples of ABS material. Therefore, the purpose of this study is to investigate the mechanical and fracture behavior of such materials and the techniques to improve such properties. Design/methodology/approach Experimental and numerical analyses have been conducted to investigate the effects of internal architecture and chopped carbon fiber (CF) fillers on the mechanical properties and mixed mode fracture behavior of the ABS samples made by 3D printing technique. Four different filling types at 70% filling ratios have been used to produce tensile and special fracture test samples with pure and CF filled ABS filaments (CF-ABS) using 3D process. A special fixture has been developed to apply mixed mode loading on fracture samples, and finite element analyses have been conducted to determine the geometric function of such samples at different loading angles. Findings It has been determined that the printing pattern has a significant effect on the mechanical properties of the sample. The addition of 15% CF to pure ABS resulted in a significant increase in tensile strength of 46.02% for line filling type and 15.04% for hexagon filling type. It has been determined that as the loading angle increases from 0° to 90°, the KIC value decreases. The addition of 15% CF increased the KIC values for hexagonal and line filling type by 64.14% and 12.5%, respectively. Originality/value The damage that will occur in ABS samples produced in 3D printers depends on the type, amount, filling speed, filling type, filling ratio, filling direction and mechanical properties of the additives. All these features are clearly dependent on the production method. Even if the same additive is used, the production method difference shows different microstructural parameters, especially different mechanical properties.

Effects of Heat Treatment on Microstructures and Properties of Ti811 Alloys

2011 ◽  
Vol 117-119 ◽  
pp. 1032-1035 ◽  
Author(s):  
Hui Gai Wang ◽  
Fei Wang ◽  
Yan Pei Song
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
Grain Boundary ◽  
Intergranular Fracture ◽  
Primary Phase ◽  
Solution Hardening ◽  
Treatment Conditions ◽  
Type Of Fracture ◽  
Brittle Intergranular Fracture

Mechanical properties and microstructures of Ti811 alloys under different heat treatment conditions were studied. The results show that the microstructures of Ti811 alloy consist of α, massive β and grain-boundary β after normal annealing. The intensity and hardness decreased, while the ductility increased. After double annealing, the primary phase α reduced and needle-like secondary α〞 was formed. The massive β and grain-boundary β changed into intergranular β gradually. The microstructure was relatively uniform. Then the intensity and hardness increased, the ductility decreased when compared to general annealing. The needle-like secondary α〞and metastable β would break down into dispersed α and β after solution hardening and aging. The combination properties of alloys would be improved. According to fractography of titanium alloy, the fracture mechanism of the Ti811 alloy was dissociation - brittle intergranular fracture, which was a type of fracture between the intergranular fracture of brittle and cleavage fracture.

Morphology and atomic structure of segregated grain boundaries in Cu-Sb

1992 ◽  
Vol 50 (1) ◽  
pp. 254-255
Author(s):  
R. W. Fonda ◽  
D. E. Luzzi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Atomic Structure ◽  
Copper Alloys ◽  
Polycrystalline Materials ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

The properties of polycrystalline materials are strongly dependant upon the strength of internal boundaries. Segregation of solute to the grain boundaries can adversely affect this strength. In copper alloys, segregation of either bismuth or antimony to the grain boundary will embrittle the alloy by facilitating intergranular fracture. Very small quantities of bismuth in copper have long been known to cause severe grain boundary embrittlement of the alloy. The effect of antimony is much less pronounced and is observed primarily at lower temperatures. Even though moderate amounts of antimony are fully soluble in copper, concentrations down to 0.14% can cause grain boundary embrittlement.

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