Effect of different heat treatment on mechanical properties and microstructure of laser welding CoCr-NiCr dissimilar alloys
10.3321/j.issn:1002-0098.2008.11.014
- VernacularTitle:两种热处理方式对激光焊接钴铬-镍铬异种合金力学性能和组织结构的影响
- Author:
Rui-Ying LIANG
1
;
Chang-Yi LI
;
Ya-Jing HAN
;
Xin HU
;
Lian-Yun ZHANG
Author Information
1. 天津医科大学口腔医学院
- Keywords:
Welding;
Laser;
Dental alloys;
Dissimilar alloy
- From:
Chinese Journal of Stomatology
2008;43(11):689-692
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the effect of heat treatment and porcelain-fused-to-metal(PFM) processing on mechanical properties and microstrueture of laser welding CoCr-NiCr dissimilar alloys. Methods Samples of CoCr-NiCr dissimilar alloys with 0.5 mm thickness were laser-welded single-side under the setting parameters of 280 V, 10 ms pulse duration. After being welded, samples were randomly assigned to three groups, 10 each. Groupl and 2 received heat treatment and PFM processing, respectively. Group 3 was control group without any treatment. Tensile strength, microstructure and element distribution of samples in the three groups were tested and observed using tensile test, metallographic examinations, scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS) analysis. Results After heat treatment and PFM processing,tensile strength of the samples were (537.15 ± 43.91 ) MPa and (534.58±48.47) MPa respectively, and elongation rates in Group 1 and 2 were (7.65 ± 0.73)% and (7.40±0.45)%. Ductile structure can be found on tensile fracture surface of samples and it was more obvious in heat treatment group than in PFM group. The results of EDS analysis indicated that certain CoCr alloy diffused towards fusion zone and NiCr side after heat treatment and PFM processing. Compared with PFM processing group, the diffusion in the heat treatment group was more obvious. Conclusions Heat treatment and PFM processing can improve the mechanical properties and microstructure of welded CoCr-NiCr dissimilar alloy to a certain degree. The improvements are more obvious with heat treatment than with porcelain treatment.
