This Small Business Innovation Research (SBIR)Phase I project will develop and validate a tool to support a manufacturing innovation specifically, the powder metallurgy process to produce highly loaded automotive transmission gears. Powder metallurgy (P/M) processes offer an excellent combination of shape forming capability and material utilization, making the technology ideal for manufacturing highly loaded automotive transmission gears. Powder forging and recently developed surface densification processes combines shaping capability and nearly pore-free materials in critical areas in order to overcome strength limitations of the P/M materials. However, P/M processes have a high degree of variability, which makes optimization of process parameters imperative. This project will perform model testing of materials under rolling contact fatigue, which is one of the failure criteria of gears. The broader impacts (commercial significance) from this project will be on material science and processing. This project will provide the capability to study crack initiation and propagation under rolling contact fatigue conditions. This will lead to a new and better understanding of crack formation mechanisms and crack growth under constant and variable compressive stresses. It allows combining material properties obtained by classical methods such as micro-hardness, fracture mechanics, and microstructure analyses with rolling contact fatigue strength. It leads to a better understanding of the effect of process variables, heat treatment parameters, and material behavior under real operational conditions. The focus of this project is on P/M processes. However, the results will change the way gears and bearings of pore-free materials are being designed and manufactured. Improved gears and bearings will increase the efficiency of transmissions, therefore indirectly reducing energy consumption
