UMBC Mechanical Engineering researchers Sal Nimer and Prof. Marc Zupan, in collaboration with Naval Surface Warfare Center, Carderock Division scientist Dr. Jennifer Wolk, are studying the effects of friction stir welding on the local mechanical properties of a Ti alloy. The research is characterizing and developing the next generation structural materials for Naval vehicle systems. Their recent work was has been featured on the cover of the journal Advanced Engineering Materials.

Micro-tensile samples were utilized as shown in the figure extracted from a friction stir welded (FSW) plate of Ti-5111 and mechanically tested to failure in order to measure local material properties. The experimentally determined mechanical properties are linked down to the micro-structural regions that develop during the FSW process as described by Marc Zupan and co-workers

The abstract from the manuscript is below:

Location and Orientation Specific Material Property

Evaluation of Friction Stir Welded Ti-5111:

A Microsample Approach**

By Salahudin Nimer, Jennifer Wolk* and Marc Zupan*

This work presents microsample measured mechanical properties of a friction stir welded (FSW) plate of Ti-5111. Property measurements and fractographic deformation observations were made as a function of discrete locations within the weld [stir zone (SZ), boundaries, base metal (BM)]. Properties in the longitudinal direction are compared to transverse measurements made at the same locations. Compared to the BM the longitudinal direction shows strength and ductility increases throughout the weld. The outer SZ showed mechanical properties in the longitudinal direction to be similar to the SZ properties in the transverse direction. These observations and measured properties serve to link the local material properties to the complex flow, heat, and deformation imparted to the material during the FSW process.