METASTABLE R-PHASE IN Fe-Cr-Mo AND Fe-Cr-W ALLOYS

The precipitation behaviour of Fe-Cr-Mo and Fe-Cr-W alloys during aging has been ex- perimentally studied.It was found that in the early stage of aging,a metastable R phase pre- cipitated in both alloys,it was transformed into stable μ-phase,Laves-phase,X-phase or σ-phase in the later stages.The crystallographic structure of metastable R-phase is rhombohedral with lattice parameters of a=0.9075 nm and α=74.45°.The chemical compo- sition of R-phase is Fe-(27.5—34.9)Mo-(0—25.5)Cr and Fe-(28.9—33.0)W-(9.36— 21.0)Cr in at.-% in Fe-Cr-Mo and Fe-Cr-W system,respectively.

常用牙科合金与铁铬钼软磁合金激光焊接件的拉伸性能评价

目的:评价激光焊接常用牙科合金与铁铬钼软磁合金后的拉伸性能。方法:铸造钴铬合金、镍铬合金拉伸试件,随机分组并分别与铁铬钼软磁合金试件用激光焊接机焊接,以激光焊接同种钴铬合金拉伸试件为对照组。利用万能拉伸试验机测试焊接后试件的抗拉强度、0.2%屈服强度,利用扫描电镜分析断裂口,并分别进行比较。结果:激光焊接铁铬钼软磁合金与钴铬合金、镍铬合金的抗拉强度、0.2%屈服强度与激光焊接同种钴铬合金无统计学差别。激光焊接铁铬钼合金与镍铬合金的断裂口呈韧性断裂,激光焊接铁铬钼合金与钴铬合金的断裂口呈韧性-解理混合型断裂,而激光焊接钴铬合金的断口呈准解理断裂。结论:从拉伸性能方面考虑,激光焊接铁铬钼软磁合金与钴铬合金、镍铬合金可应用于磁性固位体构件的焊接。

激光焊接铁铬钼合金与钴铬合金的机械性能

目的:测试激光焊接铁铬钼软磁合金与钴铬合金的机械性能,为临床应用提供参考。方法:采用国产Nd:YANG程控激光焊接机焊接铁铬钼软磁合金与钴铬合金,以激光焊接钴铬合金作为对照。利用Instron万能拉伸实验机测试焊接后的拉伸强度、0.2%屈服强度,作断裂口的扫描电镜分析,并分别进行比较。结果:激光焊接铁铬钼软磁合金与钴铬合金的拉伸强度、0.2%屈服强度与对照组无差别。激光焊接铁铬钼合金与钴铬合金的断裂口呈韧性-解理混合型断裂,而激光焊接钴铬合金的断口呈准解理断裂。结论:激光焊接铁铬钼软磁合金与钴铬合金的机械性能可满足临床需要。