Predicting the Precipitation Hardening Response of Particle Strengthened Alloys Hardened by Ordered Precipitates

Abstract

A model/method was developed for predicting the precipitation hardening response of particle strengthened alloys hardened by ordered precipitates based on the microstructure, composition, and heat treatment, and utilizing a minimum number of experimental tests. The overall approach was based on the dislocation particle interaction mechanics, particle growth and coarsening, thermodynamics, and particle strengthening mechanisms applicable to precipitation hardened alloys. The model/method evaluates, from a minimum number of experimental tensile tests, several of the microstructural constants necessary in determining the precipitation strengthening response of a particle strengthened alloy. The materials that were used as vehicles to demonstrate the model were precipitation hardenable aluminum-lithium-zirconium and nickel-aluminum alloys. Utilizing these demonstration alloys, the method used a minimum number of four tensile tests to predict the variation in strength with aging time, aging temperature, and composition, for the underaged, the peak-aged, and the overaged conditions. Predictions of the precipitation strengthening response were made using the Wagner particle distribution model and the predicted results using this distribution model compared well with the experimental yield strength results.