摘要
采用静平衡凝固技术制备了Cu含量为90wt%、不同Ni/Si原子比的Cu-Ni-Si合金,采用扫描电镜(SEM)、能谱分析(EDS)和X射线衍射仪(XRD)对合金的显微组织和相组成进行了分析,利用差热分析(DSC)考察了合金熔体在冷却过程中的相转变行为。研究结果表明,Ni/Si原子比对Cu-Ni-Si合金显微组织的影响可归因为α-Cu晶粒内部析出的δ-Ni2Si相数量的变化和晶界相在Cu-Si和Ni-Si化合物之间的选择。δ-Ni_2Si相数量的变化与初生α-Cu内部Ni、Si原子的浓度密切相关,而晶界相的相选择则是Cu-Si和Ni-Si金属间化合物相之间竞争的结果。随着Ni/Si原子比的增加,残余液相中Ni原子浓度增加增高,具有更负形成焓Ni-Si金属间化合物逐渐从竞争中胜出,导致晶界相从Cu-Si化合物向Ni-Si化合物的转变。
Cu-Ni-Si alloys with 90wt% Cu and 10wt% （Ni＋Si） of different Ni/Si atomic ratios were prepared under a near-equilibrium solidification condition. The microstructures were observed by scanning electron microscope （SEM）. The phase composition was identified by X-ray diffraction （XRD）. The phase transformations during the solidification process were analyzed by differential scanning calorimetry （DSC） under an Ar atmosphere. Results show that the effects of Ni/Si atomic ratios on the microstructures of Cu-Ni-Si alloys can be mainly ascribed to the variation of the amount of δ-Ni2Si phase formed in the inner of a-Cu grains and the selection of grain boundary phase between Cu-Si and Ni-Si phases. The former is controlled by the Ni and Si concentrations in the primary a-Cu grains and the latter is a result of the competition between Cu-Si and Ni-Si intermetallics. With the increase of Ni/Si atomic ratio, Ni-Si intermetaUics gradually win from the competition due to its lower heat of formation and the increase of Ni content in the inter-granular residual liquid. As a result, grain boundary phase changes from CusSi phase to Ni3Si phase gradually.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2015年第12期3050-3054,共5页
Rare Metal Materials and Engineering
基金
National Natural Science Foundation of China(51174161)
Special Research Foundation of Xi’an University of Technology(2013TS002)
Natural Science Foundation of Shaanxi Province(2013JQ6006)
Industrial Research Project of Science and Technology Department(2013K09-13)
Educational Official Scientific Research Foundation(2013JK0899)
Foundation of Key Laboratory of Electrical Materials and Infiltration Technology(2011HBSZS009)
Special Foundation of Key Disciplines of Shaanxi Province,State Key Laboratory of Solidification Processing in NWPU(SKLSP201213)
