Study on the Microstructure and Mechanical Properties of 17-4 PH Stainless Steel Depending on Heat Treatment and Aging Time
Study on the Microstructure and Mechanical Properties of 17-4 PH Stainless Steel Depending on Heat Treatment and Aging Time
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17-4 PH不锈钢随热处理和时效时间的显微组织和力学性能研究
DOI：
10.4028/www.scientific.net/ssp.118.15
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Y. Rhyim
中科院分区：
文献类型：
--
作者：
W. Yoo;Jong Hoon Lee;K. Youn;Y. Rhyim
研究了17-4 PH不锈钢在时效、固溶时效、400 °C长期时效和回复处理等热处理过程中的组织和力学性能，以更好地理解时效脆化现象。随着热处理时间的延长，δ铁素体的长度逐渐减小，随着体积分数的降低，δ铁素体的细长形逐渐向球形转变。固溶处理后的试样主要由板条马氏体和少量细长δ铁素体组成。固溶处理后的试样中，马氏体基体中存在少量球状颗粒，而δ-铁素体中没有发现沉淀物。随着时效处理温度的升高，强度降低，韧性提高。固溶热处理后，在400 °C长期时效过程中，δ铁素体中析出了fcc结构的富Cu颗粒。这种析出导致长期时效后的时效硬化，伴随着伸长率和夏比V形缺口能量吸收的降低。经回复处理后，强度和延伸率得到恢复，fcc-Cu析出相几乎完全溶解在δ铁素体基体中。
The microstructures and mechanical properties of 17-4 PH stainless steel at each steps of heat treatment, such as homogenizing, solid solution treatment followed by aging treatment, longterm aging at 400 °C, and recovery treatment, in order to obtain a better understanding of the embrittlement phenomena on aging, was investigated. As the homogenizing treatment time increased, the length of δ-ferrite decreased and elongated shape of δ-ferrite turned to sphere shape with the decrease of volume fraction. The solution treated specimen mainly consists of lath martensite with a small fraction of elongated δ-ferrite. The spherical particles existed a little in the martensite matrix, while no precipitates were found in the δ-ferrite at the solution treated specimen. As the aging treatment temperature increased, the strength decreased while the toughness increased. The fcc Cu-rich particles precipitated in the δ-ferrite during the long-term aging at 400 °C after the solution heat treatment. This precipitation causes the aged hardening after long-term aging accompanied by decreases in elongation and charpy V-notch energy absorption. The strength and elongation was restored after recovery treatment and the fcc-Cu precipitated were almost dissolved into the δ-ferrite matrix.