Undercooling heredity of Cu70Ni30melt solidified in
non-catalytic nucleation coated mould①
non-catalytic nucleation coated mould①
(1. School of Mechanical Engineering, Xi′an Jiaotong University, Xi′an 710049, P.R.China;
2. State Key Laborotary of Solidification Processing, Northwestern Polytechnical University,
Xi′an 710072, P.R.China)
2. State Key Laborotary of Solidification Processing, Northwestern Polytechnical University,
Xi′an 710072, P.R.China)
Abstract: A new concept of undercooling heredity is developed to evaluate the undercooling ability in a non-catalytic nucleation coated mould, where alloy melts were highly undercooled previously. Before the heredity experiment a noncatalytic nucleation composite glass-lined coating (B-F) was prepared on the inner surface of mould and the Cu70Ni30alloy was selected to perform undercooling experiment in the B-F non-catalytic coating mould. Its ratio of undercooling heredity
was 0.76. The results prove that the B-F coating is an ideal non-catalytic media for purified Cu70Ni30alloy melts due to its small contact angle between the melt and coating layer. Considering that various microstructures form under different undercoolings, two critical undercoolings,ΔT1andΔT2, and their corresponding microstructures of Cu70Ni30alloy are well defined. Moreover, it is found that the manned-trigging solidification in the non-catalytic coating mould could be used to get directional undercooling dendrite structure while the melt undercooling is larger than the critical undercoolingΔT2.
was 0.76. The results prove that the B-F coating is an ideal non-catalytic media for purified Cu70Ni30alloy melts due to its small contact angle between the melt and coating layer. Considering that various microstructures form under different undercoolings, two critical undercoolings,ΔT1andΔT2, and their corresponding microstructures of Cu70Ni30alloy are well defined. Moreover, it is found that the manned-trigging solidification in the non-catalytic coating mould could be used to get directional undercooling dendrite structure while the melt undercooling is larger than the critical undercoolingΔT2.
Key words: Cu70Ni30alloy; non-catalytic nucleation coating; undercooling heredity