Transient analysis of residual strain during heat treatment of multi-material engine blocks using in-situ neutron diffraction

摘要

Aluminum engine blocks with gray iron cylinder liners are prone to tensile residual stresses along the cylinder bores, which may cause distortion and reduce engine efficiency. This study pioneered the application of in-situ neutron diffraction to measure the residual strain in the cylinder bores of Al engine blocks as a function of time during solution heat treatment, simulated at the spectrometer. This involved designing and incorporating a unique heating system for the engine blocks. The results indicated gradual relief in residual strain with time due to creep until strain was completely relieved. Furthermore, post-treatment cooling led to the development of tensile residual strain due to thermo-mechanical mismatch between the gray iron liners and the surrounding Al alloy. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.