The effects of processing condition and fatigue on ultra-large self thermal plastic deformation in NiTi shape memory alloy fiber actuated aluminum metal matrix composites

点击翻译按钮获取中文摘要

A coupled materials processing - experimental testing - mathematical modeling program will study how variations in processing time-temperature conditions effect the strength of the self thermal-plastic response of NiTi shape memory alloy fiber actuated aluminum metal matrix composites, and will investigate how the development of very high internal stresses in the material influence mechanical fatigue behavior. Preliminary results have shown that a properly processed and prepared NiTi shape memory alloy fiber actuated aluminum metal matrix composite (SMA-MMC) will exhibit very large, self imposed thermal-plastic compressive deformation under heating. Unfortunately, very little is presently known about the processing sensitivity and thermo-mechanical-fatigue behavior of the material. We therefore propose the following three major tasks: Task 1: Systematically measure how controlled variations in high temperature hot press consolidation processing conditions effect the shape recovery of the resulting SMA-MMC, and determine the mechanism(s) responsible for the material performance changes. Task 2: Perform a tensile cycle fatigue endurance study, identifying the fatigue damage development process in the material. Task 3: Mathematically model the self thermal plastic response of the material accommodating general variations in matrix strength, matrix flow properties, fiber volume fraction, fiber transformation properties, and temperature histories. The overall goal of the program is to provide a quantitative design tool for the scientific development of safety and cost critical commercial and military applications.