Structure/Property Relationships in a Rapidly Solidified and Annealed Ternary Iron Aluminide

1990 ◽  
Vol 213 ◽  
Author(s):  
B. Décamps ◽  
M.A. Gibsont ◽  
A.J. Morton ◽  
A. Wolfenden
Keyword(s):  
Room Temperature ◽  
Prolonged Exposure ◽  
Domain Size ◽  
Tensile Fracture ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Diffraction Patterns ◽  
The Times ◽  
Rapidly Solidified ◽  
Cast Condition

ABSTRACTRapidly solidified strips of Fe66.5-A128.5-Cr5 alloy with the addition of 0.5wt.% TiB2, were produced by planar flow strip casting. Correlations of the microstructure and room temperature mechanical properties were made for strips in the as-cast condition and after annealing at 1273K for periods up to 4hrs. The results showed that grain size, tensile strength, ductility, hardness and Young's modulus were very stable for the times investigated. Studies of tensile fracture surfaces revealed essentially 100% transgranular cleavage in the ascast strip with a greater tendency for intergranular failure after prolonged exposure to high temperatures. TEM studies of this alloy revealed diffraction patterns characteristic of DO3 ordering but the dislocations observed in both ascast and deformed specimens were those typical of the B2 structure without any extended APBs. This is attributed to the very fine DO3, domain size . At room temperature <111> slip is predominant.

Structure-Property Relationships of Poly(Butylene Terephthalate)/Polyolefin Blends

1998 ◽  
Vol 18 (1-2) ◽  
pp. 17-30 ◽  
Author(s):  
D.S. Lee ◽  
J.K. Doo ◽  
B. Kim ◽  
J. Kim
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Structure Property ◽  
Melt Mixing ◽  
Butylene Terephthalate ◽  
Polyolefin Blends ◽  
Structure Property Relationships ◽  
Acrylic Ester ◽  
Discrete Phase

Abstract Structure-property relationships of poly(butylene terephthalate) (PBT) / polyolefin (PO) (80/20) blends modified by a reactive compatibilizer, ethylene-acrylic ester-glycidyl methacrylate terpolymer (BAG), were investigated as part of studies on toughening of PBT. POs used for the study were ethylene propylene rubber (EPR), low-density polyethylene (LDPE), and high-density polyethylene (HDPE), whose deformabilities were different at room temperature. It was observed that the particle size of PO in the discrete phase was the smallest when the EAG content was 8~12 wL%. Shear viscosity of the blends increased as the particle size was decreased. It seems that the morphology and rheological properties of the blends were affected by graft copolymers formed in situ from EAG and PBT during melt mixing. Brittle-tough transition of impact strength of the PBT/EPR/EAG blends was observed when the EAG content was increased from 0 to 4 wt% at room temperature. However, blends of PBT/LDPE/EAG and PBT/HDPE/EAG showed brittle-tough transition with increasing the EAG content from 8 wt% to 12 wt%. It is postulated that toughening of the PBT depends on the deformability of the discrete PO particle as well as its size.

On the Structure-Property Relationship of Rapidly Solidified High Temperature Application Aluminium Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
A.J.S. Chowdhury ◽  
T. Sheppard
Keyword(s):  
High Temperature ◽  
High Temperature Strength ◽  
Structure Property ◽  
High Temperature Application ◽  
Structure Property Relationships ◽  
Structure Property Relationship ◽  
Temperature Application ◽  
Rapidly Solidified ◽  
Relationship Of ◽  
Strength And Ductility

AbstractThe phases responsible for high temperature strength and ductility of Al-Fe based alloys, specifically Al-Fe-Mo alloys, have yet to be unambiguously identified. The phases appear to vary slightly under different experimental and processing conditions. This poses some queries concerning the reproducibility of mechanical properties of these alloys. In this paper an attempt is made to address these points and focus on the structure-property relationships of Al-Fe-Mo and Al-Fe-V rapidly solidified powder alloys.

Structure/Property Relationships and Applications of Rapidly Solidified Aluminum Alloys

1981 ◽  
Vol 8 ◽  
Author(s):  
C. M. Adam
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Aluminum Alloys ◽  
Thermomechanical Processing ◽  
Structure Property ◽  
Turbine Engine ◽  
Structure Property Relationships ◽  
Plant Stage ◽  
Spherical Droplets ◽  
Rapidly Solidified

ABSTRACTDuring the last five years Pratt & Whitney Aircraft has developed rapid solidification powder metallurgy and consolidation techniques to produce advanced aluminum alloys. A centrifugal rotary atomization device with forced high velocity helium convective cooling has been developed to pilot-plant stage, to produce aluminum alloys of novel compositions for advanced gas turbine engine applications. Rapidly solidified aluminum alloys solidify as spherical droplets up to 100 μm diameter with cooling rates of 105 — 106 K/sec, and demonstrate new microstructural features which have been exploited to develop elevated temperature mechanical properties. Alloys have been developed for 400 — 500°F fan and compressor applications that have traditionally used titanium alloys, and this paper reviews the microstructural evolution of rapidly solidified structures during thermomechanical processing.

The Influence of Surface Termination and Domain Structure on the Photochemical Reactivity of SrTiO3 and BaTiO3

2001 ◽  
Vol 7 (S2) ◽  
pp. 1062-1063
Author(s):  
Jennifer L. Giocondi ◽  
Gregory S. Rohrer
Keyword(s):  
Photochemical Activity ◽  
Metallic Silver ◽  
Local Measurement ◽  
Structure Property ◽  
Thermal Etching ◽  
Structure Property Relationships ◽  
Polycrystalline Ceramic ◽  
Backscattered Electron ◽  
Diffraction Patterns ◽  
Conventional Ceramic Processing

The crystallographic orientation and atomic termination layer of oxide catalysts are known to influence their reactivity. The objective of this work was to measure how the relative photochemical reactivities of two ternary titanates vary with surface orientation and composition. The surface structure property relationships derived from these observations can be used to define optimized photocatalyst microstructures.To measure the relative reactivity of surfaces with different orientations, crystallites (∽ 20 μm in diameter) in a polycrystalline ceramic were examined individually. First, polycrystalline specimens of BaTiO3 and SrTiO3 were synthesized using conventional ceramic processing. Surfaces for analysis were prepared by polishing and thermal etching in air. The surface orientations of selected grains in the sample were then determined from backscattered electron diffraction patterns recorded in a scanning electron microscope. to make a local measurement of the photochemical activity of each grain, we used a well established probe reaction (the reduction of aqueous Ag+ to Ag0) that deposits metallic silver on the surface as a reaction product.

Imaging of crystalline structure in thermotropic copolymers

1990 ◽  
Vol 48 (4) ◽  
pp. 226-227
Author(s):  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Diffraction Analysis ◽  
Crystalline Structure ◽  
Dark Field ◽  
Advanced Materials ◽  
Structure Property ◽  
Razor Blade ◽  
Transparent Films ◽  
Structure Property Relationships ◽  
Transmission Electron ◽  
Diffraction Patterns

Electron-diffraction analysis and dark-field (DF) imaging of crystalline structure in highly-oriented polymers have been used effectively to discern structure-property relationships in these materials. Diffraction patterns of some thermotropic copolyesters, such as those composed of 4-hydroxybenzoic acid (B) and 2,6-hydroxynaphthoic acid (N) or those from N and terephthalic acid/hydroxyaniline (TA), exhibit sharp equatorial reflections, suggestive of finite intermolecular ordering, and aperiodic meridional maxima, indicative of random intramolecular sequencing (see inset of Fig. 1). However, diffraction analysis of a related thermotropic copolymer, composed of B and isophthalic acid/hydroquinone (IQ), reveals periodic meridional maxima and ill-defined equatorial reflections. DF imaging in conventional transmission electron microscopy is utilized here to permit accurate assessment of the crystallite morphologies in these two chemically-related families.Samples of the B-N and N-TA materials were provided by the Hoechst-Celanese Corporation, and the B-IQ copolymer was supplied by ICI Advanced Materials. Electron-transparent films were produced by first heating a small chunk of each material on freshly-cleaved rocksalt to a predesignated temperature. The samples were then quickly sheared with a razor blade, and the resultant films were quenched on an aluminum block.

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