15-5PH不銹鋼的時(shí)效硬化行為及耐蝕性能

15-5PH不銹鋼的時(shí)效硬化行為及耐蝕性能Aging hardening behavior and corrosion resistance of 15-5PH stainless steel

利用透射電鏡(TEM)、X射線(xiàn)衍射(XRD)、洛氏硬度、動(dòng)電位極化曲線(xiàn)和交流阻抗等方法對(duì)15-5PH不銹鋼時(shí)效后的組織轉(zhuǎn)變、時(shí)效硬化行為及其在Cl-溶液中的耐蝕性能進(jìn)行研究。結(jié)果表明：時(shí)效溫度較低(低于450 ℃) 時(shí)，析出的富Cu相與基體保持共格關(guān)系，其硬度和耐腐蝕性能都較高。當(dāng)時(shí)效溫度達(dá)到550 ℃時(shí)，富Cu相長(zhǎng)大，出現(xiàn)了逆變奧氏體，且隨時(shí)效時(shí)間的延長(zhǎng)而增多，導(dǎo)致硬度下降，但耐蝕性能有所提高；當(dāng)時(shí)效溫度升高至620 ℃時(shí)，富Cu相呈短棒狀，且失去與基體的共格關(guān)系，逆變奧氏體繼續(xù)增多，強(qiáng)化效應(yīng)完全消失，但耐蝕性能得到改善。

The microstructure transformation, aging hardening behavior and corrosion resistance of 15-5PH stainless steel were studied by XRD, TEM, HRC, polarization curve and electrochemical impedance spectroscopy. The results show that the hardness and corrosion resistance due to Cu-rich phase have coherent orientation relationship with matrix when the aging temperature is lower than 450℃. The Cu-rich phases coarsening and the reversed austenite are observed in the specimen, when the aging temperature reaches to 550 ℃. Moreover, the amount of reversed austenite increases with the increase of aging time. So, the hardness decreases but the corrosion resistance increases. When the aging temperature reaches 620 ℃, the Cu-rich phases exhibit elliptical shape and destroy the coherent relation with the martensite matrix, meanwhile, the reversed austenite continues to increase. As a result, the precipitation hardening effect disappears, however, the corrosion resistance is improved.

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