Study On Fabricating And Performance Of Cerium And Praseodymium Addition On The Aluminum Alloy

With the increased interest in environmental protection and energy saving, aluminum alloy welcomed by most people because of their specific functions.however,the aluminum alloy is soft and easy to poor adhesion, high coefficient of friction and abrasion resistance shortcomings and more,limits its application to some degree.When the Si component was above 6%,eutectic Si is characterized by coarse acicular or plate-like morphology Which seriously affects the performance of aluminum alloy.so modifying aluminum-base alloy can improve the mechanical properties very much.As a whole,complex modifying agent’s effect was better than single modifying agent,and complex modifying agent have superposition.Rare earth as a modifier have a direct relationship with atomic radius,a value of 1.646 is proposed as the ideal ratio of the atomic radius of the impurity-element compared to silicon for an element to cause modification.The atomic ratio of Praseodymium and Cerium were 1.573 and 1.556 which were close to the ideal value and therefore Praseodymium and Cerium were predicted to result in modification.Praseodymium and Cerium modifying aluminum-base alloy can improve the mechanical properties very much.The abrasion-resistance is related to hardness,overall,the higher the hardness,the better the abrasion-resistance.So the study of aluminum alloy wear resistance is prolonging part life and its application fields can be enlarged.In this paper,using multiple sets of test and theoretical analysis model.Highenergy ultrasonic grading preparation of ternary mass alloy then added to Al-7Si-Mg aluminum alloy fabrication the Rare earth-aluminum alloy with different Praseodymium/Cerium additions.The sound flow model simulation of the high-energy ultrasound in the melt mixing effect in the process of smelting.So can control the accuracy of the rare earth addition,avoid burned.The model of DarkenGurry solid solubility elliptical shows that solid solubility of Praseodymium/Cerium in Al-matrix is low.Praseodymium/Cerium be segregation in grain boundary or phase boundary but solid solute in other compounds and in the form of intermetallic compounds. dynamics model simulation of the diffusion of solute in the melt.And uses the empirical electronic theory of solids and molecules(EET) to analyze the constitutive relation of mechanical properties and the valence electrons.Fault Tree Analysis(FTA) using a simple mathematical logic analysis method reverse analysis of the tensile fracture morphology to explain the way and mechanism of fracture.The fracture morphology and microstructure are analyzed,the results showed that the growth mechanism from inherent steps into Tradition Phenomenological Rate(TPRE) mechanism,adding right amount of Praseodymium/Cerium,makes the grain refinement and improving mechanical properties.With the Praseodymium/Cerium addition, the fracture mode will be changed.Unmodified,the fracture mode is transgranular fracture.However,appear the inter-and trans-granular fracture mode after rare earth modified.The study of abrasion-resistance of RE-Al alloy shown that the wear mechanism of alloy with 0.6% Praseodymium/Cerium addition is particle wear.with the increasing slippery velocity,the wear resistance of specimen were evidently improved and the stability were optimized.The wear mechanism has changed from thermal softening、delamination and fatigue wear at low slippery velocity to three-body abrasion under the moderate velocity to steady wear at high speed.L13(45) Factor-Level orthogonal project were designed and the effect of heat-trating process on the microstructure and mechanical properties were discussed.The solution temperature is too high,overheating shows meit-back eutectic ball and meit-back triangle.Eutectic silicon is small in size and high spheroidization when the solution parameter for solution temperature is 510 degrees and solution time is 6 hours.Comprehensive analysis,the optimum heat treatment process is A3B2C3D1,that with 0.6% Praseodymium/Cerium addition,solution temperature is 510 degrees and solution time is 6 hours and ageing temperature is 180 degrees and ageing time is 4 hours.