Directionally-solidified (DS) GTD-111 is a Ni-base superalloy designed to withstand damage occurring in the first and second stage blades of gas-powered turbines. Because of the distinctive microstructure of this material, the manner in which fatiguecreep-environment damage mechanisms interact to initiate cracks is sensitive to grain structure and chemical composition. Along with fatigue cyclin...

Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low ∆K, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = Kmin/Kmax). The near threshold accelerated FCG rates are exacerbated by increased levels...

This study examined the ability of pole-bound hawk-kites to protect maturing fields of corn from blackbird damage. Hawk-kites were placed over half of each experimental field. Damage on the hawk-kite side was slightly, but not significantly, less than on the unprotected side as measured by the percent of ears damaged by birds, total amount of grain lost to birds, or percent of crop damaged by b...

mechanical damage due to harvesting, handling, and other processes is an important factor that affects the seeds quality. seed damage results in lower grain value and more storability problem and reduces seed germination and seedling vigor and subsequent yield of crops. tests were conducted to determine the percentage of physical damage (ppd) and percentage of loss in germination (plg) of wheat...

One of the yet unresolved engineering problems is forecasting the creep lives of weldment in a pragmatic way with sufficient accuracy. There are number of obstacles to circumvent including: complex material behavior, lack of accurate knowledge about the creep material behavior specially about the heat affected zones (HAZ),accurate and multi-axial creep damage models, etc. In general, creep life...

_______________________________________________________________ vi In order to investigate the cause of early electromigration failure in Cu vias, an infrared (IR) microscope technique was developed to detect weak via before catastrophic failure. The grain structure of a via (grain size and grain orientation) is determined to be not critical to the early failure. Instead, our study shows that p...