Effect Of Rare Earth Yb On Microstructure And Properties Of Extruded ADC12

In recent years,the development of new energy vehicles has been rapid.In order to achieve lightweight,the body of automobiles,parts and chassis of automobiles,etc.,basic aluminum alloys are used.In order to protect and enhance the overall quality and performance of new energy vehicles,higher requirements are placed on the mechanical properties and wear resistance of aluminum alloys.To this end,this article will use a variety of processes and methods to improve the overall mechanical properties and wear resistance of aluminum alloys,in order to further tap the application potential of aluminum alloys in new energy vehicles.At the same time,the study of the principles associated with each process will provide theory and reference for the future development and application of aluminum alloys in new energy vehicles.The main research content of this article is as follows:The content of rare earth Yb is between 0 and 0.9 wt%.As the content of rare earth Yb increases,the spacing between the arms of the secondary branches will become smaller and smaller;the coarse,massive Fe-rich phase will change into small pieces.Fe-rich phase;coarse long needle-like silicon phase will be converted into a short rod,and finally from a short rod into a small fibrous.The addition of rare earth Yb after ADC12 will produce a rare earth phase consisting of three elements of Al,Si,Yb.The rare earth phase can provide a nucleation site for the Fe-rich phase or a heterogenous nucleation site for the Fe-rich phase,and is conducive to refinement of the Fe-rich phase.The fracture of the original substrate ADC12 was a cleavage fracture,that is,a brittle fracture,which was mainly caused by a thick long needle-like silicon phase.The fracture of ADC12 with 0.9wt.% Yb was composed of two kinds of fractures.The fracture was mainly composed of a large number of dimples and a few cleaved cleavages,so the fracture mode was quasi-cleavage fracture.Second,there are a large number of intact ?-Al phases on the fracture surface,as well as rare-earth and Fe-rich phases containing cracks.The fractures are caused by crack growth on the rare-earth and Fe-rich phases and cracking of the phase and phase boundaries..When the addition amount of rare earth reached 0.9wt.%,the tensile strength,elongation andhardness reached the maximum,which were 267.89 MPa,4.16% and 107.3HV,respectively.The best solid solution process of 0.9wt.% Yb/ADC12 is 520°C/1h.After 520°C/4h,the Fe-rich phase is hardly or hardly dissolved into the matrix,and a small amount of rare earth phases can be broken.Most of the rare earth phases remain basically unchanged.After 0.9wt.% Yb/ADC12 was hot extruded,the ?-Al phase was elongated along the extrusion direction and the adjacent ?-Al phases in the extrusion direction were connected to each other,resulting in a decrease in the inter-arm spacing between the two branches..In addition,the fibrous eutectic silicon phase is broken into granules and the distribution is more uniform.The coarse Fe-rich phase and the rare earth phase are broken into small rods,blocks,or granules,distributed along the extrusion direction.The hot-extruded 0.9wt.% Yb/ADC12 had the smallest secondary inter-arm spacing and the smallest eutectic silicon size and the most uniform distribution.After 520°C/1h+170°C/10 h,the fastest eutectic silicon spherodizing rate is 0.9wt.% Yb/ADC12 after hot extrusion,followed by hot-extrusion of ADC12 or 0.9wt.% Yb/ADC12.The original matrix ADC12.Therefore,both the rare earth Yb and the hot extrusion can promote the spherulization of the eutectic silicon phase,shorten the time of solution treatment and reduce the size of the eutectic silicon phase.T6 heat treatment,rare earth Yb,hot extrusion can effectively reduce the amount of wear of ADC12,and this effect is further expanded under higher loads.The most obvious effect is ADC12 after triple modification of rare earth metamorphism,hot extrusion and heat treatment.T6 heat treatment,rare earth Yb,and hot extrusion all reduce the friction and wear coefficient of ADC12 to a certain extent.Among them,the largest increase is in the modification of rare earths,hot extrusion and heat treatment of ADC12,followed by rare earth Yb and hot extrusion.Finally,T6 heat treatment.