CAJ | 학술논문

在约化压缩变形温度tr=T/Tg 为77 K/T g≤t r<t rc1、t rc1≤t r<t rc2和t rc2≤t r<Tx/T g 时,一般块体非晶合金的压缩变形行为分别对应不均匀脆性断裂、非牛顿流变和牛顿流变；当应变速率约为10-4 s-1时,临界约化压缩变形温度trc1在0.839~0.920之间,trc2=1.011；随着应变速率的降低,块体非晶合金由不均匀的脆性断裂转变为非牛顿流变的t rc1、由非牛顿流变转变为牛顿流变的t rc2均降低。低tr 压缩变形试样表面的剪切带特征明显,但高tr 压缩变形由于均匀变形和热影响作用使剪切带不明显,且块体非晶合金的塑性随剪切带数量的增加而提高；随着tr 的升高,块体非晶合金的断口显微组织演化过程分别为复杂不均匀的脉状纹络、较均匀的脉状纹络、熔滴状和岩浆流状组织。另外在极低约化压缩温度tr下 Ni60 Pd20 P17 B3和 Ti40 Zr25 Ni3 Cu12 Be20块体非晶合金表现出非牛顿流变行为。非晶在一定温度的压缩变形会导致部分或所有非晶纳米晶化。
재약화압축변형온도tr=T/Tg 위77 K/T g≤t r<t rc1、t rc1≤t r<t rc2화t rc2≤t r<Tx/T g 시,일반괴체비정합금적압축변형행위분별대응불균균취성단렬、비우돈류변화우돈류변；당응변속솔약위10-4 s-1시,림계약화압축변형온도trc1재0.839~0.920지간,trc2=1.011；수착응변속솔적강저,괴체비정합금유불균균적취성단렬전변위비우돈류변적t rc1、유비우돈류변전변위우돈류변적t rc2균강저。저tr 압축변형시양표면적전절대특정명현,단고tr 압축변형유우균균변형화열영향작용사전절대불명현,차괴체비정합금적소성수전절대수량적증가이제고；수착tr 적승고,괴체비정합금적단구현미조직연화과정분별위복잡불균균적맥상문락、교균균적맥상문락、용적상화암장류상조직。령외재겁저약화압축온도tr하 Ni60 Pd20 P17 B3화 Ti40 Zr25 Ni3 Cu12 Be20괴체비정합금표현출비우돈류변행위。비정재일정온도적압축변형회도치부분혹소유비정납미정화。
In this paper,the compressive deformation behavior,samples surfaces and fracture microstructure characteristics have been reviewed at different temperatures and strain rates for bulk metallic glasses (BMGs). BMGs behave like inhomogeneous brittle fracture,non-Newtonian fluid and Newtonian fluid mode respectively at reduced compressing temperature tr=T/Tg ranging of 77 K/Tg≤tr<trc1 ,trc1≤tr<trc2 and trc2≤tr<Tx/Tg. When strain rate was about 10-4 s-1 ,normally trc1=0.839-0.920 and trc2=1.011.With the strain rate decrea-sing,the critical reduced compressive temperatures trc1 (changing from inhomogeneous brittle fracture mode to non-Newtonian fluid one)and trc2 (from non-Newtonian fluid one to Newtonian fluid one)were decreased.At low tr ,plasticity of BMGs increased with the number of shear bands,which were obvious on the samples sur-faces,but at high tr they were even unobserved because of homogeneous deformation and heat.With tr increas-ing,fracture microstructure characteristics changed from complex and inhomogeneous vein-like pattern to hom-ogeneous one,then to droplets,or lava-flow pattern.In addition,Ni60 Pd20 P17 B3 BMG and Ti40 Zr25 Ni3 Cu12 Be20 BMG behaved like non-Newtonian fluid mode during compressing at tr=0.127-0.503.Finally,this paper also discussed the phenomenon of nanocrystallization during the compression deformation.