How to regulate the isothermal growth rate of polymer spherulite without changing its molecular composition?

A new method has been invented to control the spherulite growth rate of isothermally crystallized PBS without changing its molecular composition.

Coarsening of Particles in Coarse Grain Heat-Affected Zone for Ti Microalloyed Steels

The coarsening behavior of Ti (CxN1-x) particles in CGHAZ for Ti-microalloyed steel has been studied after different welding thermal cycles corresponding to heat inputs 30, 60, 100kJ/cm using Gleeble-3800 thermo/mechanical simulator and transmission electron microscopy. Cuboid TiN and a lot of ellipsoidal or elongated particles VC, M3C and M23C6 are observed in the base metal. After welding thermal cycle with peak temperature of 1350°C, irregular particles existed in base metal have also been dissolved even at the lowest heat input of 30kJ/cm. TiN Particles coarsening are observed in CGHAZ with the increase of heat inputs that is just related to dissolution and reprecipitation of particles and irrelevant to isothermal growth of particles. Keywords: microalloyed steel; coarse grain heat-affected zone; TiN particles

The Effect of Temperature and Time on the Formation of a Reaction Interlayer During Aluminizing of a Carbon Steel

ABSTRACTA kinetic study was performed on the growth of a reaction interlayer between molten Al and carbon steel substrates at temperatures between 665 to 820°C by holding Al/flux/steel assemblies, in a tube furnace, at temperature for times up to 120 min. An Ar atmosphere and a K-Al-F based flux were used to enable spreading of molten Al on the steel substrates. Chemical and microstructural characterization of the samples revealed that the interlayer is composed of FeAl3 and Fe2Al5, being the second phase significantly thicker. The Fe2Al5 phase grows toward the steel with a tongue like morphology. Isothermal growth profiles of the reaction interlayer followed a parabolic behavior, meaning that at the beginning the reaction is very rapid and once that a continuous interlayer is formed the growth of the interlayer is controlled by interdifussion of species across the interlayer.