Research On The Microstructure And Properties Of Rapidly Solidified And Horizontal Continuous Casted Cu-Zr-Al Alloys

Cu-Zr-Al alloy was chosen as the main research object in this paper. Alloy rods with different Zr and Al content were prepared by copper mold casting method which has a rapid solidification rate. Microstructure and properties of casted alloy rods were studied. Cold rolling and aging treatment were done to the alloy and the effects of aging time and temperature on electrical conductivity and mechanical properties of the alloy were studied. The optimum aging process has been found. Horizontal continuous casting craft was studied and microstructure and properties of continuous casted alloy rods were analyzed.Injection copper mold casted Cu90Zr10-xAlx (x=1,3,5,7,9; at.%) alloy rods with a diameter of 2 mm were composed of ?-Cu and Cu5Zr phase, Al is solid-soluted in ?-Cu. Cu90Zr9Al1 alloy is composed of ?-Cu+Cu5Zr eutectic matrix and dispersively distributed fibrous Cu5Zr phase. Cu90Zr7Al3 and Cu90Zr8Al5 alloy are composed of dendrite ?-Cu and ?-Cu+Cu5Zr eutectic structure between the dendrites. However, Cu90Zr3Al7 and Cu90Zr1Al9 are composed of ?-Cu grains and ?-Cu+CusZr eutectic structure between the grains. The alloy rods have an outstanding mechanical properties. Cu90Zr9Al1?Cu90Zr7Al3 and Cu90Zr5Al5 alloy rods have a compressive yield strength of 1513 MPa,1066 MPa and 812 MPa respectively. Vickers hardness of 420,326 and 250 respectively. The high mechanical properties of alloy rods come from the fine microstructures, when the cooling rate dropped, the microstructure become coarse and the mechanical properties also dropped.Copper mold casted Cu99Zr0.5Al0.5 alloy rod with a diameter of 20 mm is composed of fine, equiaxed grains and a few eutectic phases near the grain boundary. The grains were stretched and changed into banded structure after cold rolling. The tensile strength of the cold-rolled alloy increase and the electrical concuctivity of the cold-rolled alloy decrease with the raising of rolling rate. The Vickers hardness of 70% cold rolled Cu99Zr0.5Al0.5 alloy increased first and then decreased with the extension of the aging time, the electrical conductivity of the alloy increased quickly at the initial stage and then became stable. The optimum overall performance of Cu99Zr0.5Al0.5 alloy was gained under 450?×1 h aging treatment, with a Vickers hardness of 172, tensile strength of 460 MPa, enlongation of 16.4% and electrical conductivity of 60.1% IACS.A self-designed horizontal continuous casting equipment was used to prepare continuous casted alloy rods. Pure cooper and Cu90Zr9Al1 alloy rods with nice surface quality were prepared through changing the casting speed, casting temperature, pull-stop circulation time, pressure difference and cooling water flow, etc. The continuous casted Cu90Zr9Al1 alloy rod is composed of alternate distributioned ?-Cu and CusZr phases. It's compressive fracture strength is 996.0 MPa, tensile strength is 865.7 MPa and electrical conductivity is 12.3% IACS.