本文選題：Cu-15Ni-8Sn + 冷變形　； 參考：《江蘇科技大學》2017年碩士論文

【摘要】：本文分別采用中頻感應爐與高頻感應爐對Cu-15Ni-8Sn合金進行熔煉制樣,探索合金鑄態(tài)枝晶間距對后續(xù)熱處理過程中組織與性能的影響。在分別添加微量Cr、Zr、Si、Nb、Ti、Mn元素后,研究這些微量合金元素對Cu-15Ni-8Sn合金在均勻化退火與固溶處理、冷變形與時效處理過程中組織與性能的變化。確定能延緩低熔點不連續(xù)沉淀產物析出的條件,從而改善合金塑性成形工藝性能。與此同時,研究合金元素含量對Cu-15Ni-8Sn合金調幅分解組織與性能的影響。研究表明:鑄態(tài)枝晶間距縮減至11μm左右的Cu-15Ni-8Sn合金經840℃×8h均勻化退火與800℃×1h固溶處理后組織已趨于均勻,當枝晶間距達到50μm時Cu-15Ni-8Sn合金在同等熱處理工藝條件下,溶質擴散不均勻,依舊存在殘余未溶組織。而初生呈亮白色的未溶組織屬于富錫相。溶質擴散不均勻的Cu-15Ni-8Sn合金分別在80%或60%冷軋變形后,80%冷軋變形試樣在400℃×0.5h時效處理后達到硬度峰值394HV,60%冷軋變形試樣在400℃×1h時效處理后達到硬度峰值392HV,但隨時效時間的繼續(xù)延長其硬度值皆急劇下降。而溶質擴散較均勻的Cu-15Ni-8Sn合金,經60%冷鐓粗變形及400℃×5h時效后達到395HV的硬度峰值。微量Nb與Si能延緩Cu-15Ni-8Sn合金在均勻化退火過程中的溶質擴散效果,經60%冷鐓粗變形的試樣邊緣有裂紋,時效處理時不連續(xù)沉淀產物呈提前析出趨勢,400℃×5h時效后的硬度分別為300HV與365HV;添加微量Zr的Cu-15Ni-8Sn合金60%冷鐓粗變形后試樣邊緣未出現(xiàn)裂紋,但在400℃×5h時效處理后大量析出不連續(xù)沉淀產物,而硬度僅有287HV;添加微量Ti的Cu-15Ni-8Sn合金在60%冷鐓粗變形后邊緣雖有裂紋產生,但在時效階段不連續(xù)沉淀產物的析出與變形量成正比,試樣邊緣高變形區(qū)的析出與生長較快、試樣中心區(qū)域析出與生長較平穩(wěn),400℃×5h時效處理后硬度達到393HV;添加微量Mn的合金不僅60%冷鐓粗變形后試樣邊緣未開裂,在400℃×5h時效處理后試樣邊緣高變形區(qū)也未大量析出不連續(xù)沉淀產物,硬度值為387HV;添加微量Cr的合金在400℃×5h時效處理后的組織與性能略遜于含Mn合金,硬度值為369HV。對更多Mn元素含量的Cu-15Ni-8Sn合金組織與性能進行研究,結果表明添加0.87wt%Mn與0.38wt%Mn在延緩不連續(xù)沉淀產物的效果相近,隨Mn含量的提高Cu-15Ni-8Sn合金時效硬化的峰值時間被延遲。因此,添加0.38wt%Mn的Cu-15Ni-8Sn合金綜合工藝性能最佳。
[Abstract]:In this paper, Cu-15Ni-8Sn alloy samples were prepared by medium frequency induction furnace and high frequency induction furnace, respectively, and the effect of as-cast dendrite spacing on microstructure and properties of Cu-15Ni-8Sn alloy during subsequent heat treatment was investigated.The microstructure and properties of Cu-15Ni-8Sn alloy during homogenization annealing, solution treatment, cold deformation and aging treatment were studied after adding trace elements of Cr-ZrZirn, Si-Nb and Ti-Mn respectively, and the microstructure and properties of the alloy were studied during homogenization annealing, solution treatment, cold deformation and aging treatment.The conditions which can delay the precipitation of discontinuous precipitation products at low melting point are determined, and the process properties of alloy plastic forming are improved.At the same time, the effect of alloy element content on the microstructure and properties of Cu-15Ni-8Sn alloy was studied.The results show that the microstructure of the as-cast Cu-15Ni-8Sn alloy reduced to about 11 渭 m after homogenization annealing at 840 鈩，

本文編號：1734110