Phase Particle Distribution Research Articles

On the effects of second phase distribution on the fracture behaviour of two superplastic aluminium alloys

The significant scatter observed in the elongation to fracture of specimens taken from a single, industrially processed sheet for two Al alloys has been traced to changes in the value of the strain rate sensitivity index (m) and also to the specimen to specimen variation in the concentration and distribution of second phase particles/inclusions. It is shown that these three variables of m, second phase particle content and distribution affect the width of tear ridges, the size of clusters of grains that pull out as a whole during fracture, their connectivity and the extent to which cavitation can be suffered before final fracture. The consequences of these effects for specimen ductility are discussed.

Second phase particle distribution and secondary recrystallisation

Second phase particle distribution and secondary recrystallisation

Hydrodynamical Evolution of QGP-Fluid with Phase Transition and Particle Distribution in High Energy Nuclear Collisions

We numerically solve the (3+ I)-dimensional hydrodynamical equation for a perfect fluid with phase transition to analyze cylindrically symmetric space-time expansion of a quark-gluon plasma fluid possibly produced in high energy nuclear collisions. The temperature dependences of ther­ modynamical quantities are so designed as to give the QeD-like phase transition through a semi phenomenological transport theory based on a quantum Langevin equation. The effects of the phase transition and the transverse expansion on the temperature distribution of the fluid are discussed in detail, by making use of the numerical solution. Finally we derive the transverse momentum distribution and rapidity distribution of produced pions.

Hydrodynamical Evolution of QGP-Fluid with Phase Transition and Particle Distribution in High Energy Nuclear Collisions

Hydrodynamical Evolution of QGP-Fluid with Phase Transition and Particle Distribution in High Energy Nuclear Collisions

Analytical description of the solid phase particle distribution in a mechanically agitated system

A mathematical model of the solid particle random motion in a turbulent liquid flow was developed which resulted in an unconventional form of diffusion equation. The diffusion equation derived describes quantitatively the local extremes of the solid phase concentrations in the charge mixed which were verified experimentally. The comparison of the experimental and calculated distribution of local concentrations in the system shows an adequate qualitative agreement. The system consisted of a cylindrical conical-bottomed vessel with baffles and cylindrical draft-tube. A six-blade impeller with inclined (at α = 45° plane blades was used for agitating.

偏晶系Ａｌ‐ＰｂおよびＡｌ‐Ｂｉ合金の凝固組織

The dependence of L2 phase particle distribution in the matrix of monotectic alloys on such solidification parameters as temperature gradient, growth rate and cooling rate was examined. Al-10wt%Pb and Al-3.4 to 30wt%Bi alloys were solidified unidirectionally in an insulating mold placed on a copper chill and non-directionally in graphite, copper and water-cooled copper molds. The alloys containing a liquid miscibility gap solidify accompanying heavy gravity segregation. This segregation is caused by coarsening of L2 phase droplets and their migration during cooling in the miscibility gap. Casting monotectic alloys containing Pb up to 10wt% and Bi up to 20wt% in a copper mold ensures fine and homogeneous dispersion of L2 phase particles.

The effects of alloying and processing on the fracture characteristics of aluminum sheet

The effects of composition and processing on microstructure and fracture behavior of Al-Zn-Mg-Cu (7075 type) alloys were investigated. The microstructural variations involved changes in second phase particle size and distribution and in grain structure. Second phase particles in three size ranges were investigated: (1) coarse insoluble particles involving Fe at various levels, (2) finer intermediate particles involving Cr or Zr varied in size by choice of homogenizing practice, and (3) fine aging precipitates varied in size by choice of aging practice. The use of high temperature, long-time homogenizing practices to produce coarse intermediate particles also resulted in recrystallization and grain growth, particularly in the Zr-bearing Al-Zn-Mg-Cu alloys. Grain size and shape were found to strongly affect toughness; plane stress fracture toughness [of 12-in. (0.30 m) wide center notched panels] at a given yield strength level differed by a factor of three between a fully recrystallized, coarse equiaxed grain structure to an unrecrystallized lamellar structure. Smaller effects of second phase particles distribution were found in the Al-Zn-Mg-Cu alloys. The trends observed in a fatigue crack growth rate study of the same materials will be discussed.

Quantitative microstructural characterization of aligned eutectics by electrical analog modeling

The formal theory of conduction in multiphase systems as derived by Rayleigh is compared with experimental results from fabricated Bi-Cu composite model systems having known minor phase particle shape and well defined phase particle distributions. The development of a rigorous three dimensional fibrous analog model by the modification of existing analog concepts and utilization of the Rayleigh analysis coupled with resistance measurements performed on more complex Bi-Cu composite systems is presented. This fiber analog model is applied to the directionally aligned Sb-InSb eutectic utilizing available resistivity data. Via this model a quantitative microstructural characterization, consistent in two orthogonal directions, is achieved and these data are presented.