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Showing 1 to 20 of 40 for “"grain refinement"”.
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Grain refinement in steel castings
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Metallurgy, 1960.
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Grain refinement in cast titanium 6-aluminium 4-vanadium by hydrogenation, deformation and recrystallisation
… wrought counterparts. Therefore, microstructure refinement is required in order to optimize these mechanical properties. The aim of this work is to refine the as-cast Ti6Al4V microstructure by reducing its prior beta grain sizes and changing its Widmanstatten morphology. Refinement was achieved …
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Effects of yttrium additions on grain refinement and cracking susceptibility in Ti-6Al-2Nb-1Ta-0.8Mo weld metal, The
Includes bibliographical references.
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Assessment of the effect of grain refinement on the solidification characteristics of Al-Si-Cu eutectic cast alloy using thermal analysis technical (CA-CCTA)
… of this research is to evaluate the the grain refinement treatments with the additions of (1.6-9.7) wt.% of TiB5, using Cooling Curve Thermal Analysis. Furthermore, the study also investigated the roles of TiB5 on microstructural constituents and formation of intermetallic, Furthermore, …
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Mechanisms of Microstructure Formation Under the Influence of Ultrasonic Vibrations
… nucleation is the major contributor to the grain refinement. Ultrasonication at minimal supercoolings is expected to give maximal grain refinement. Dendrite fragmentation has not shown to be a significant contributor to the grain refinement. Dendrite fragmentation is maximal if done by …
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Microstructure and tensile performance evolution during Titanium - 6 Aluminium - 4 Vanadium (Ti-6Al-4V) temporary hydrogen treatment
… of hydrogen on microstructure evolution, grain refinement and tensile performance. It exposes the unarticulated relationship between hydrogen and titanium aluminide (Ti3Al) as a gap in literature that has been sustained by the pervasive use of the repeated nucleation framework. It …
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The influence of rough rolling conditions on austenite evolution in peritectic microalloyed plate steels
… heating rate and soaking time on the austenite grain size. Heating rate of 7.5 �C/min and constant soaking time of 30 minutes were used for roughing simulations as this closely simulated the slab�s centre thermal profile. The roughing strain sequence was varied from small (0.07 _/ pass), …
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Stress corrosion cracking behavior of friction stir processed ultrafine grained light metal alloys
… microstructural evolution especially matrix grain size on the corrosion and stress corrosion properties of the alloys. A relationship between grain size and corrosion rate for Mg-Y-RE alloys was envisaged and power law type behavior was proposed. Ultrafine fine grained (UFG) microstructure …
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Effect of nano-scale twinning on the fracture, fatigue and wear properties of copper
Grain refinement in materials has been one of the most common strategies for improving the strength of materials. However this comes at the price of reduced ductility, fracture toughness and stable fatigue crack propagation life. It has been shown that controlled introduction of nano scale growth …
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Nanostructural Evolution of Hard Turning Layers in Carburized Steel
… transformations. These transformations occur via grain refinement or thermal phenomena depending upon cutting conditions. The aim of this work is to engineer the near surface nanoscale structure and properties during hard turning by altering strain, strain rate, temperature and incoming …
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Characterization of Carbonaceous Exsolvate from Metal Melts
… likely due to strengthening mechanisms such as grain refinement and that the carbonaceous nanostructures do not play a significant role in steel strength.
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Effect of incremental equal channel angular pressing (I-ECAP) on the microstructural characteristics and mechanical behaviour of commercially pure titanium
… and performance of CP-Ti by nano-structuring or grain refinement.;Severe plastic deformation (SPD) is an established method for introducing extreme grain refinement in metals. The technique imparts high plastic strain to the material without significantly changing the sample dimensions and is …
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Development and characterization of nanostructured steels and high entropy alloys for nuclear applications
… <p>Because SPD is effective at achieving grain refinement, this technique was used to obtain material having a high volume fraction of grain boundaries which act as effective radiation induced defect sinks. This work aims to study the pre-irradiation microstructure and irradiation …
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Effect of the Mn Additive on Cu-Zn-Al Shape Memory Alloy
… memory alloy was developed and studied. The grain refinement, eutectic structure, and the precipitates were investigated. The microstructure of the alloy has been observed and analyzed; grains are significantly refined by the addition of manganese. The lamellar structure of the alloy has also …
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Bauschinger effect in Nb and V microalloyed line pipe steels
… microalloying element content, to provide grain refinement, solid solution and precipitation strengthening. During the UOE forming of large diameter (more than 400 mm) welded pipes the strength drop from plate to pipe, as a result of reverse deformation (the Bauschinger effect), depends on …
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Controlling microstructure of nanocrystalline thermoelectrics through powder processing
… due to enhanced phonon scattering at grain boundaries. However, the excess free energy of these interfaces renders them inherently susceptible to grain growth, therefore there is a need for materials with enhanced thermal stability. Despite this, little is known about the relevant …
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Friction stir welding of high temperature alloys
… the stirred zone.</p> <p>FSW resulted in refined grain structure in ODS alloys by dynamic recrystallization mechanism. A critical finding was 'strain induced dispersoid agglomeration'. For Ti-6Al-4V alloy, transformed ß microstructure formed composed of fine acicular α phase (~500 nm in …
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Grain size effects on the fatigue response of nanocrystalline materials
… is known to be influenced significantly by grain size. Based on a wealth of experimental results obtained from microcrystalline metals, where the grain size is typically greater than 1 um, it is widely recognized that an increase in grain size generally results in a reduction in the fatigue …
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