Effect Of Filling Velocity On Microstructure And Mechanical Properties In Different Locations Of ZL205A Alloy Castings

The low-pressure casting method for forming different thickness of the cylindrical ZL205 A to study the effects of different filling rate on microstructures and mechanical properties of different locations of ZL205 A in this paper.The microstructureof the as-cast alloy and after T6 heat treatment were observed and found that microstructuresof ZL205 A alloy grain boundariesare clear and there are many microscopic shrinkage. The microstructure of as-cast is mainlyAl matrix phase. The main component of the second phase Al2 Cu grain boundary and block section of the second phase. Grain boundary becomes smallafter T6 heat treatment. Most of the grain boundary phase solid solution matrix and grains size has increased.Through calculating on the grain size at each position of as-cast structure.Filling velocity no significant effect on the grain size of ZL205 A alloyunder the conditions of wall thickness of 45 mm. The grain size of the as-cast alloys grow largerwhen the filling speed is greateratthicknessof wall is 15 mm conditions. When the filling velocity increased from 40mm/s to 80mm/s, the average grain diameters increased by about 43μm atthe lower part of the casting. Different positions of the alloy of different height have different grain sizes. The grain sizesbecome larger from top tobottom. As-cast microstructure and grain size is limited by several factors filling velocity.Thickness of casting wallet al. the effect of each factor is differentunder different conditions.After testsof the mechanical properties of ZL205 A alloy after T6 heat treatment found that the thinner the thickness of the casting. The effectof the fillingspeed on mechanical properties is greaterand the elongation of the alloy is more sensitiveto the changeof velocity. When casting wall thickness of 15 mm, the tensile strength and elongation of the alloy are the highest when the filling speed is 80mm/s. The tensile strength is greaterwhen the casting position is lowerand the thinner wall castings. The effect of heightis much greater totensile strength. The elongation of wall thickness of 45 mm, 15 mm increases with height reduced, the elongation of wall thickness of 25 mm decreaseswith height reducedat speed filling of 80mm/s.Dense of castwill improvealloy performancewhen filling velocity greater and the time of pressure become longerduring solidification. But the filling rate increases will lead to increased grain size, thereby reducing the performance of the alloy. Both factors interact together to affect the properties of the alloy.The highest elongation of ZL205 A up to 22% this paper. Glaciers pattern is clear of brittle fracture on the lower elongation and can be observed microscopic shrinkage.The shrinkageof fracture reduce gradually and tearing ridge and dimple increase with the elongation of the alloy increases. But intergranular fracture morphology remain.