THE HIGH CYCLE FATIGUE and FRACTURE BEHAVIOR OF PM AI-Cr-Fe ALLOY CONSOLIDATED BY PLASMA PRESSURE COMPACTION

摘要

Powders of an Al-7Cr-lFe alloy were prepared by the technique of Gas Atomization Reaction Synthesis (GARS) at Ames Laboratory, Ames, Iowa. A pre-alloyed stock of the aluminum alloy was melted and atomized in an inert environment. The atomized particles were classified as less than 45 micron sized powders. The powder particles were then consolidated in a vacuum environment using the technique of plasma pressure compaction (P~2C~(TM)). The samples were pulsed at 150℃ for 10 minutes and subsequently consolidated at 550℃ under a pressure of 40 MPa for 10 minutes. In this paper, the high cycle fatigue response and final fracture behavior of the aluminum alloy is presented and discussed. The tensile deformation, cyclic stress amplitude-controlled fatigue properties and fracture characteristics of the aluminum alloy are highlighted at two different test temperatures. The influence of test temperature and load ratio on maximum stress versus fatigue life response is detailed. An attempt is made to elucidate the key mechanisms governing stress response and fatigue fracture characteristics in light of the competing and mutually interactive influences of intrinsic microstrucrural features, deformation characteristics of the constituents of the material, maximum stress, load ratio and test temperature.