(1. 中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083;
2. 廣西冶金研究院，南寧 530023)
摘 要: 通過在喂料中添加石墨改變注射成形17-4PH不銹鋼組織中的碳含量，研究不同碳含量對MIM 17-4PH顯微組織和力學(xué)性能的影響。結(jié)果表明：在燒結(jié)態(tài)和固溶時效態(tài)試樣中，碳含量少于0.16%(質(zhì)量分?jǐn)?shù))的相組織主要由馬氏體和少量的鐵素體構(gòu)成。隨著碳含量的逐漸升高，冷卻過程中奧氏體未能完全轉(zhuǎn)變成馬氏體，組織中出現(xiàn)奧氏體，在碳含量為0.16%的燒結(jié)態(tài)和固溶時效態(tài)試樣中，其顯微組織為馬氏體和奧氏體共同組成的雙相組織，而且奧氏體相含量隨著碳含量增加而逐漸增加；在碳含量達(dá)到0.25%以上時，試樣的顯微組織完全轉(zhuǎn)變?yōu)閵W氏體，導(dǎo)致試樣的表觀硬度下降，抗拉強(qiáng)度下降，伸長率提高。
關(guān)鍵字: MIM17-4PH不銹鋼；碳含量；相轉(zhuǎn)變；力學(xué)性能
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Guangxi Research Institute of Metallurgical, Nanning 530023, China）
Abstract:Graphite was added into the 17-4PH stainless steel to vary the carbon content. The effect of carbon content on the microstructure and mechanical properties of metal injection molded 17-4PH stainless steel was investigated. The results show that the samples by solid solution and aging treatment, mainly consist of martensite and a small amount of ferrite at carbon content less than 0.16%. Austenite fails to completely transform into martensite in the cooling process and the amount of austenite increases gradually with the carbon content increasing. The samples consist of both martensite and austenite at carbon content of 0.16%. Then, the samples mainly consist of austenite when carbon content is more than 0.25%. This leads to a decrease in hardness and tensile strength, while the elongation increases.
Key words: MIM17-4PH stainless steel; carbon content; phase transformation; mechanical property
