(鋼鐵研究總院 高溫材料研究所，北京 100081)
摘 要: 粉末冶金(P/M)合金中由于原始顆粒邊界(PPB)的存在，在力學性能試樣斷口上呈現(xiàn)顆粒間斷裂。通過SEM、TEM、AES等手段對采用等離子旋轉(zhuǎn)電極(PREP)制粉+直接熱等靜壓(HIP)成形工藝的一種P/M鎳基高溫合金低周疲勞(LCF)斷口上顆粒間斷裂的形貌和類型進行了表征和分析，討論了PPB的起因及其與疲勞裂紋在顆粒間萌生、擴展斷裂機制的關(guān)系和顆粒間斷裂對疲勞壽命的影響。結(jié)果表明：PREP+HIP工藝成形的鎳基合金中的PPB由多種綜合因素造成；PPB降低了合金的斷裂韌性，直接影響顆粒間斷裂程度；在LCF斷口上，單顆粒成為裂紋源的占顆粒間斷裂斷口總數(shù)的67%，多顆粒裂紋源占17%，其他占16%；顆粒間斷裂在LCF斷口上的分布表征分為4級；顆粒間斷裂越嚴重，對合金疲勞壽命影響越大。
關(guān)鍵字: 粉末冶金高溫合金；原始顆粒邊界；顆粒間斷裂；低周疲勞斷口
（Central Iron and Steel Research Institute, High Temperature Material Institute, Beijing 100081, China）
Abstract:The mechanical property of sample fractures shows inter-particle ruptures due to the existence of prior particle boundary (PPB) in P/M superalloys. The inter-particle rupture morphological characterization and type on low cycle fatigue (LCF) fracture of a nickel-based P/M superalloys by plasma rotating electrode process (PREP) plus hot isostatic press (as-HIP) were analyzed by SEM, TEM and AES. The causes of PPB formation and relationships between PPB and mechanism of fatigue crack initiation and crack propagation at inter-particle, as well as the effect of inter-particle rupture on LCF life, were discussed. The results show that PPB in P/M nickel-based superalloys processed by PREP +HIP is caused by many composite factors, PPB reduces the fracture toughness, and directly affects the degree of inter-particle rupture, a single particle to be the crack origin on LCF fracture accounts for 67% of the total fractures, multi-particle 17%, other 16%. The distribution characterization of inter-particle fracture on LCF fractograph can be divided into four grades, the more serious inter-particle fractures affects fatigue lives more.
Key words: P/M superalloy; prior particle boundary; inter-particle rupture; low cycle fatigue fracture
