Abstract
An investigation has been conducted to determine the influence of solution heat treatment parameters on T6 properties of unmodified and Sr-modified A356.2 alloys. The effects of solution temperature and time were studied with ASTM B-108 test bars cast in sand molds and in permanent molds. The microstructural changes occurring during heat treatment have been investigated by metallographic and image analysis techniques. The results indicate that the effect of Sr modification is to increase the spherodization rate and lower the coarsening rate of Si particles. Silicon particle characteristics are strongly influenced by the solution temperature. Extremely high coarsening rates can be obtained at temperatures greater than 560C. Solution treatment at these temperatures, however, has a detrimental effect on mechanical properties because of grain boundary melting. It has been established that solution times can be reduced significantly in modified samples. Increasing the solution temperature from 540C to 550C enhances the strength properties.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
