Influence of weld cooling rate on microstructure and mechanical properties of alloy 718 weldments

被引：83

作者：

Sivaprasad, K. ^{[1
]}

Raman, S. Ganesh Sundara ^{[2
]}

机构：

[1] Natl Inst Technol, Dept Met & Mat Engn, Tiruchirappalli 620015, India

[2] Indian Inst Technol, Dept Met & Mat Engn, Madras 600036, Tamil Nadu, India

来源：

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE | 2008年 / 39A卷 / 09期

关键词：

D O I：

10.1007/s11661-008-9553-y

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Even though alloy 718 is the best for welding among all nickel-base superalloys, the formation of the Laves phase in welds is a major concern. The presence of this phase drastically degrades mechanical properties of the welds. To study the influence of weld cooling rate on microstructure and mechanical properties of alloy 718 weldments, two distinct welding processes were adopted-gas tungsten arc (GTA) and electron beam (EB) welding. The EB welding resulted in finer and relatively discrete Laves phase in lower quantity due to higher cooling rates prevailing in this process. On the other hand, due to lower cooling rates, GTA weld fusion zones exhibited coarse Laves with higher niobium. Depletion of the primary strengthening element niobium in the surrounding regions of Laves promoted crack propagation. Because EB welds had finer and lower amount of Laves, EB weldments exhibited superior mechanical properties compared with GTA weldments.

引用

页码：2115 / 2127

页数：13

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