| In the previous studies on ZnAl alloys,a certain performance of the alloy is usually regulated,and the comprehensive evaluation of the alloy performance is less.Strengthening the friction and wear properties of ZnAl alloys will inevitably lead to different degrees of weakening of plasticity and corrosion resistance.It is still a challenge to comprehensively enhance the properties of ZnAl alloys to meet their application as industrial structural components.In this paper,ZA27 alloy with good comprehensive performance was selected as the research object.The effects of different contents of Mn and Sr on the microstructure and properties of ZA27 alloy were compared and studied.The morphology and characteristics of the second phase and the influence of the interaction between different alloying elements on the microstructure and properties of the alloy were explored.The internal relationship between the microstructure and properties of the alloy was clarified to realize the regulation of the microstructure and the morphology of the second phase.In this paper,the influence of alloying elements Mn and Sr on the microstructure and properties of ZA27 alloy,as well as the morphology and composition of the precipitated second phase were clarified through microstructure observation,phase composition test,mechanical property test,friction and wear test and immersion corrosion test.Then,the microstructure characteristics of the alloy were measured and counted,and the influence of alloy microstructure on the properties of the alloy was quantitatively analyzed.The results show that the addition of Mn and Sr inhibits the growth of primary α-Al dendrites in ZA27 alloy,and significantly refines the α + η eutectoid microstructure.Mn has a better refinement effect on the α-Al dendrite arm,and Sr has a more obvious refinement effect on the α + η eutectoid microstructure.When 0.4 wt.% Mn is added to the alloy alone,the proportion of α + η eutectoid microstructure reaches the maximum,about 70 %,and the lamellar spacing is about 130 nm.The tensile properties and friction and wear properties of ZA27 alloy are enhanced,but the corrosion resistance is significantly reduced.When 0.1 wt.% Sr is added to the alloy alone,the proportion of α + η eutectoid structure reaches the maximum,about 60 %,and the minimum lamellar spacing is about 70 nm.The alloy has the best tensile properties,antifriction performance,and corrosion resistance.Comparing the strengthening effect of Mn and Sr on ZA27 alloy,it is also found that the fine degree of α + η eutectoid microstructure accounts for a large weight in the influence of plasticity,and makes the oxidation and corrosion of the alloy more uniform.When Mn and Sr are added to the ZA27 alloy,the distance between eutectoid α + η lamellas can not be further refined,or the proportion of eutectoid α + η microstructure is increased,but the local corrosion caused by the second phase in the alloy is effectively alleviated.When the total contents of Mn and Sr are too high,the microstructure refinement effect of the alloy is weakened.When 0.4 wt.% Mn and 0.1 wt.% Sr are added together,the wear resistance of the alloy is significantly enhanced,and the good plasticity and corrosion resistance are maintained.This paper provides a certain reference for the comprehensive enhancement of the properties of ZnAl alloys.To achieve the application of ZnAl alloys in industry,it is necessary to further design and adjust the alloy composition or carry out processings. |
