反复烧结对选择性激光熔积钴铬合金硬度的影响

Effect of repeated firing on hardness of selective laser melting cobalt-chromium alloy

目的探讨反复烧结对选择性激光熔积技术(SLM)制作的钴铬合金硬度的影响。方法用具有相同成分的钴铬合金粉末和金属块,分别运用SLM技术(SLM组)和铸造工艺(铸造组)制作,每组各制作25个圆柱形试件(10mm直径*3mm厚度),随机分成A、B、C、D、E组进行烧结,其中A组不烧结,B、C、D、E组分别烧结1、3、5、7次,在显微硬度仪上分别测量其维氏硬度,比较SLM组和铸造组的硬度。结果烧结0、1、3、5、7次后,SLM组的平均维氏硬度分别为427.9、571.3、600.4、620.9、673.3HV,铸造组的平均维氏硬度分别为354.7、374.7、429.3、440.4、449.1HV,相同烧结次数的SLM组和铸造组之间比较,其差异具有统计学意义(P<0.05)。结论烧结能增加钴铬合金的硬度,SLM钴铬合金比铸造钴铬合金硬度增加更明显;烧结前后,SLM钴铬合金均较铸造钴铬合金硬度高。

Objective To explore the effects of repeated firing on cobalt-chromium （Co-Cr） alloy＇ s hardness which is fabricated by selective laser melting （SLM）. Methods Cobalt chromium alloy powders and metal blocks with the same composition were fabricated by SLM （SLM group） and casting （cast group）, each group has 25 cylinder specimens （10mm diameter and 3mm thickness）, which randomly divided into A, B, C, D, E subgroups： group A without sintering, group B, C, D and E with 1, 3, 5 and 7 times sintering respectively. Their Vickers hardness was measured by micro-hardness tester in order to compare the Vickers hardness of SLM group and cast group. Results After 0, 1,3, 5 and 7 times sintering, the average Vickers hardness of SLM group were 427.9, 571.3,600.4, 620.9 and 673.3 HV respectively, while the average Vickers hardness of cast group were 354.7, 374.7, 440.4, 429.3 and 449.1HV respectively. There was a significant difference between these two groups with the same sintering times （P〈0.05）. Conclusion Repeated firing can increase the hardness of Co-Cr alloy, which is obviously higher in SLM group; before and after firing, Co-Cr alloy fabricated by SLM was significantly harder than the cast Co-Cr alloy.