Study On Mechanism And Microstructure And Properties Of Al-Ti-C Master Alloy Prepared By Sawdust Method

With the wide application of aluminum materials,people gradually found that the aluminum alloy contains a large amount of columnar crystal structure,which affects its performance.After long-term research by many researchers,the grain refinement treatment can make the quality of aluminum materials more excellent,and thus meet the needs of industrial production.Therefore,the study of grain refinement is of great significance to the aluminum industry.This thesis mainly introduces a new synthetic method using wood chips,K2TiF6,pure aluminum as the original material,and melting by crucible resistance furnace,and finally pouring into Al-Ti-C master alloy in cylindrical mold.The content of the article is mainly composed of three parts:the first part is the preparation process of the alloy sample and the sample grinding process.The second part is the microscopic analysis of the processed samples by X-ray diffraction,scanning electron microscopy and energy spectrum detection,and the basic reaction process in the experiment is discussed.In the third part,the refining effect of Al-Ti-C refiner on industrial pure aluminum was tested.The sample was subjected to anode coating treatment and its grain size was observed under a metallographic microscope.Finally,the refinement mechanism of Al-Ti-C is briefly explored.The experimental results show that:?1?The Al-Ti-C master alloy prepared by the wood chip method mainly contains??Al?phase,?Al₃Ti?phase,?TiC?phase and?Al₄C₃?phase.It can be easily inferred that in the process of metal cooling and crystallization,??Al?is solidified by titanium carbon particles and Al₃Ti particles as the core of the crystal nucleus,and finally the crystal grains are refined;?2?prepared by the wood chip method.SEM photograph of aluminum-titanium carbon master alloy,we can see that a large number of equiaxed crystals are distributed in the alloy samples at different multiples,the grain size is about 10⁶0 um,and many phases are gathered at the grain boundary position;3)The SEM and EDS analysis of the aluminum-titanium carbon intermediate alloy sample further on the phase appearing at the grain boundary and the second phase region in the crystal shows that the grain boundary is mainly?-aluminum matrix and a small amount of TiC phase,Al₄C₃ Phase;Al₃Ti phase,TiC phase,and trace impurity elements are segregated on?-aluminum surface in the second phase;?4?The process of synthesizing aluminum-titanium carbon intermediate alloy by wood chip method mainly has three parts,firstly K₂TiF₆and Al acts to release titanium.The wood chips then decompose and carbonize in the high temperature melt.Finally,the elements released by the previous raw material compounding reaction interact to produce Al₃Ti,TiC,and the like.?5?Calculate the component to which the Al-Ti-C alloy grain refiner should be added according to0.1%,0.2%,0.3%,0.4%,0.5%,and 0.6%of the mass of the pure aluminum sample.The results show that the average grain size of pure aluminum decreases with the increase of the refiner content,and a good refinement effect is obtained.After 0.3%,with the increase in the amount of the refiner added,the average grain size area did not change significantly,and the effect on the refining effect was small.Therefore,in order to save material cost and achieve certain alloy quality considerations,it is best to select the Al-Ti-C refiner with a blending amount of 0.3%.