Effects of W substitution on ς and χ phase precipitation and toughness in duplex stainless steels
Effects of W substitution on ς and χ phase precipitation and toughness in duplex stainless steels
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W替代对双相不锈钢中ς和χ相析出及韧性的影响
DOI：
10.1179/mst.1998.14.8.757
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发表时间：
1998
影响因子：
1.8
通讯作者：
K. Y. Kim
中科院分区：
文献类型：
--
作者：
Young‐kook Lee;K. T. Kim;Y. D. Lee;K. Y. Kim
本文研究了W对不同Mo和W含量的25 Cr-6 Ni基超级双相不锈钢在700-1050 ℃热处理后析出行为的影响。时效时，含Mo双相不锈钢的主要金属间相为σ相。在双相不锈钢中，含W的双相不锈钢在时效初期促进了χ相的析出，而抑制了σ相的析出。当在900°C时效13.5min时，25 Cr-6 Ni-3.6Mo、25 Cr-6 Ni-3.6Mo-3 W、25 Cr-6 Ni-2 Mo-3.6W和25 Cr-6 Ni-1.5Mo-4.3W的冲击能量分别降低到7、3.6、19.4和28.1J。单纯添加W会增加25 Cr双相不锈钢的时效脆性。尽管在相界处的一薄层χ相比σ相对冲击韧性有更有害的影响，但W替代双相不锈钢中的Mo并没有降低整体韧性。由于7 chi相中W的过饱和，χ相的生长速率受到阻碍。由于σ相的析出强烈依赖于Mo含量，因此在给定的时效条件下，W替代可以减少金属间化合物的总量。随着W取代量的增加，总的金属间相含量降低。
The effects of W on the precipitation behaviour of 25 Cr-6Ni base super duplex stainless steels with various Mo and W contents have been examined following heat treatments in the temperature range 700–1050°C. Upon aging, the major intermetallic phase of the duplex stainless steel containing Mo was σ phase. In duplex stainless steels containing W, χ phase precipitation was enhanced at the early stages of aging and σ phase precipitation retarded. When aged at 900°C for 13.5 min the impact energies of 25Cr-6Ni-3.6Mo, 25Cr-6Ni-3.6Mo-3W, 25Cr-6Ni-2Mo-3.6W and 25Cr-6Ni-1.5Mo-4.3W were reduced to 7,3.6, 19.4, and 28.1 J respectively. Simple addition of W increased brittleness on aging in 25Cr duplex stainless steel. Despite a thin layer of χ phase at the phase boundary having a more deleterious effect on impact toughness than σ phase, W substitution for Mo in the duplex stainless steel did not degrade the overall toughness. The growth rate of χ phase was retarded owing to supersaturation of W in the 7chi; phase. Since σ phase precipitation depended strongly on Mo content, the total amount of intermetallic could be reduced for a given aging condition by W substitution. As W substitution increased, the total intermetallic phase content decreased.