[The effect of cryotreat on tensile properties of medium melting-point and high melting-point castable alloy].
OBJECTIVE
To introduce cryotreat technique into prosthetic dentistry by testing the tensile properties of CW-H Co-Cr-Mo cast alloy before and after cryotreat and to observe the image changes by SEM to study the mechanism that changes the tensile properties of the alloy.


METHODS
15 CW-H cast alloy were divided into 3 groups, i.e. control group (G1), cryotreated group (G2) and cryotreated plus post-cryogenic treated group (G3). The gauge test technique was employed to test the modulus of elasticity. Then the strength and percentage elongation (PE) were tested. SEM images were used to analyze the mechanism that improved the tension properties of the alloy.


RESULTS
For CW-H alloy the strength and the modulus of elasticity of both G2 and G3 were effectively increased but PE effectively decreased than G1. There was no effectively difference between G2 and G3, but G3 was larger than G2. SEM images of G2 and G3 showed that secondary-carbonide separated out all over the alloy.


CONCLUSIONS
The results obtained above suggest that cryotreat is an effective method in enhancing tensile properties of CW-H Co-Cr-Mo cast alloy.
Dept. of Engineering Mechanics, Sichuan University, Chengdu, China.
Meng-shi
MS
Chen
Zhi-min
ZM
Zhu
Ning
N
Li
D003722:Dental Alloys / Q000737:chemistry*; D003735:Dental Casting Technique; D004548:Elasticity; D006244:Hardness; D013696:Temperature; D013718:Tensile Strength; D014800:Vitallium / Q000737:chemistry*
D003722:Dental Alloys; D014800:Vitallium