Influence Of Ti On The Microstructure And Properties Of The Heat-resistant Conductive Aluminum Alloy

To increase the recrystallization temperature of the traditional heat-resistant conductive aluminum alloy and improve the property of heat-resistant of alloy, Zr element is added to the aluminum alloy. It is reported that the conductivity of alloy can't be reduced significantly, but there also be a negative effect, and be some conductivity reduction. Later, some research shows that the impact resulted by Zr on conductive will be reduced effectively, when B element is added to the aluminum alloy. When the content of B and Zr is adjusted to achieving the atomic ratio 2:1 of B to Zr, the properties of the alloy become the optimum condition.There is less report about the effect upon the properties of the heat-resistant conductive Aluminum alloy, when Ti and Zr elements are added to the alloy. In this paper, the impact on the Aluminum alloy including Zr and Ti elements was studied. It studied the effect upon the microstructure, mechanical properties and electrical properties of alloys with various Ti contents. We include:1 When Ti was added to the heat-resistant conductive Aluminum Alloy, the microstructure of alloy could be refined significantly. Because Zr,Ti and B in the alloy could form ZrB2 and TiB2 particles. Then the excess Ti atomic could attach to the surface of the TiB2, and form Al3Ti.Al3Ti could be the center of heterogeneous nucleation in the Al liquid, when the liquid solidified. And the microstructure was refined.2 When the content of Zr, Ti and B in the alloy was adjusted to the atom ratio 1:2 of (Zr+Ti) to B,Zr and Ti could form ZrB2 and TiB2 particles fully, and there was no excess Ti atomic in the liquid. So there was no Al3Ti around the surface of TiB2 particles. The center of heterogeneous nucleation in the Al liquid reduced, the extent of grain refining weakened, and the grain size became larger. The microstructure of large grain size had positive effect upon the electrical properties and heat-resistant properties.3 Zr,Ti and B in alloy could form complex particles of (Zr,Ti) B2, and precipitated at grain boundaries. Those complex particles had high melting point, high hardness and better thermal stability. Those properties could generate positive effect upon the heat-resistant properties, and improved the heat-resistant properties of Al alloy. When the temperature of strength retention was 290℃,the strength of Al alloy met GB4 When the content of Ti,Zr and B in alloy was reduced appropriately, and strength and heat-resistant properties met GB, the conductivity of alloy was improved and reached at 60%IACS.