(1. 四川大學(xué) 材料科學(xué)與工程學(xué)院，成都 610065；2. 西華大學(xué) 材料科學(xué)與工程學(xué)院，成都 610039)
摘 要: 測(cè)試了Sn-3.5Ag-2Bi無鉛焊料的壓入蠕變應(yīng)力指數(shù)n、蠕變激活能Q及其結(jié)構(gòu)常數(shù)A，推導(dǎo)了壓入蠕變穩(wěn)態(tài)蠕變速率的本構(gòu)方程，總結(jié)了壓入蠕變隨溫度和應(yīng)力的變化規(guī)律以及蠕變塑性變形機(jī)制，并初步探討提高Sn-3.5Ag-2Bi無鉛焊料抗蠕變性能的有效途徑。結(jié)果表明：Sn-3.5Ag-2Bi無鉛焊料的應(yīng)力指數(shù)(n)為3.304、蠕變激活能(Q)為61.181 kJ/mol，材料的結(jié)構(gòu)常數(shù)(A)為0.679；并得出壓入蠕變穩(wěn)態(tài)蠕變速率的本構(gòu)方程；壓入蠕變的位移量隨溫度的升高和應(yīng)力的增加有規(guī)律地變大；通過分析其蠕變前后的微觀結(jié)構(gòu)和組織的變化，認(rèn)為Sn-3.5Ag-2Bi無鉛焊料蠕變塑性變形機(jī)制主要由位錯(cuò)滑移和位錯(cuò)攀移共同控制。
關(guān)鍵字: Sn-3.5Ag-2Bi無鉛焊料；壓入蠕變；應(yīng)力指數(shù)；激活能；微觀組織
（1. College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China;2. College of Materials Science and Engineering, Xihua University, Chengdu 610039, China）
Abstract:The indentation creep stress exponent (n), creep activation energy (Q) and material structure constant (A) of Sn-3.5Ag-2Bi lead-free solder were measured, and the constitutive equation of the indentation creep steady-state creep rate was derived. The law that indentation creep changes with the stress and the temperature changing and creep plastic deformation mechanisms were summarized. The effective ways of raising Sn-3.5Ag-2Bi lead-free solder anti- creep property was also discussed. The results show that the stress exponent (n) is 3.304, creep activation energy (Q) is 61.181 kJ/mol and the material structure constant (A) is 0.679. The constitutive equation of the indentation creep steady-state creep rate is also derived. The displacement of indentation creep is enlarged regularly with the rising temperature and increasing stress. Through the analysis of changes of the micro-structure and organization before creep and after creep, the plastic deformation mechanisms of Sn-3.5Ag-2Bi lead-free solder creep are dominated by both dislocation slipping and dislocation climbing mainly.
Key words: Sn-3.5Ag-2Bi lead-free solder; indentation creep; stress exponent; activation energy; microstructure
