Research On Microstructure And Properties Of High Aluminum Zn-Based Alloys

High Aluminum Zinc-base alloys have been applied as a kind of neotype non-ferrous materials in recent decades.These alloys present a lot of advantages,such as good casting properties and mechanical properties,excellent wear-resisting as well as low manufacturing cost.Up to now,they have been used instead of some traditional wear-resisting materials such as brass,bronze and Babbitt metal.The mechanical properties at room temperature,frictional wear properties and gas-tight of Zn-Al alloys with different Aluminum contents were studied. The influence of two kinds of grain-refiners on the microstructure and properties of high-alumina Zinc-base alloy was also investigated.The main results are present as follows.(1)The microstructure of alloys is consisted of dendrite a' phase,eutectoid a+ηphase,a small amount of e phase and eutectic.With the increase of Al content,the amount of a' phase increase but the amount of eutectoid(a+η)phase decrease.(2)The dimensional stability of the zinc-aluminum alloys can be improved by heat treating for which can stabilized the microstructure.Appropriate aging treatment can make the microstructure more homogenous,weaken the effectiveness of solution strengthening,reduce the strength and hardness,but enhance the plasticity and toughness.(3)Under the experimental conditions of this paper,when the load is 870N and the rotary speed is 200r/min,the wear resistance of Zn-Al alloy is better than bronze.(4)Although both 1# and 2# refiner can improve the mechanical properties and wear resistance of Zn-Al alloys,the effect of 2# refiner is more notable.(5)There is no bubble observed when the alloys were placed in the water for 5 minutes with a pressure 1MPa,which shows that all high Aluminum Zinc-base alloys prepared have good gas-tight to meet the application requirements of high voltage switch valve.