The effects of in-situ AlN particles on thermal expansion behavior of AZ91 alloy
Yunzhen Li, Tian Li, Jingchao Wang, Yunxia Sun, Jie Zheng, Changlin Yang
Abstract
The thermal expansion behaviors of AlN/AZ91 composites prepared by in-situ synthesis method were investigated. The results showed that AlN particles effectively inhibited the thermal expansion of AZ91 matrix alloy through its intrinsic low thermal expansion property as well as the mechanical interaction with matrix due to the fine and dispersed AlN particles effectively increasing the contact area and the bonding with AZ91 matrix. Then, lower thermal expansion coefficient (CTE) of (9.8–18) × 10 −6 /K from 30 °C to 200 °C was achieved in AlN/AZ91 composites with 6 vol% AlN, which was favorable to obtain the excellent structural dimensional stability. Theoretical model prediction further confirmed that AlN reinforcement particles with high bulk modulus , low CTE, and suitable volume fraction can significantly reduce CTE of AlN/AZ91 composites.