Ni-32.7at%Cu合金的调幅分解及其对再结晶织构的影响

Spinodal decomposition of Ni-32.7at%Cu alloy and its effect on recrystallization texture

采用真空感应熔炼制备Ni-32.7at%Cu及Ni-31.7at%Cu-3at%W合金坯锭,经热锻、热轧和冷轧后得到最终厚度为80μm的冷轧薄带。分别将其在1000℃×1 h再结晶退火前后于350℃保温0、30、180和360 min,并根据XRD边带峰强度、位置以及EBSD中织构含量的变化分析了其调幅分解现象及其对再结晶织构的影响。结果表明,Ni-32.7at%Cu合金薄带1000℃×1 h再结晶退火后水冷,再于350℃保温不同时间的样品中均发生了调幅分解,且调幅波长随保温时间的延长而逐渐增加;合金薄带在350℃保温不同时间后,再经1000℃×1 h退火时,孪晶比例随保温时间的延长由16%增至32%,立方织构比例由80.2%降低至14.4%。这种再结晶织构的变化归因于保温过程中调幅效应的增强;调幅分解通过形成多相组织以及孪晶结构抑制了立方取向晶粒的优先长大,同时也削弱了低温回复带来的优先形核优势,使得立方织构比例显著下降。W元素的加入抑制了调幅分解的产生,提高了立方织构比例。

The Ni-32. 7 at% Cu and Ni-31. 7 at% Cu-3 at% W alloy ingots were prepared by vacuum induction melting and two final thickness of 80 μm cold-rolled tapes were obtained after hot-forging,hot-rolling and cold-rolling. According to the change of intensity,location of side band peaks in XRD spectra and the percentage of recrystallization texture in EBSD,spinodal decomposition and its effect on texture were studied by annealing the specimens at 350 ℃ for 0,30,180,360 min before and after recrystallization annealing. The results indicate that spinodal decomposition occurrs in all specimens annealed at 1000 ℃ for 1 h,followed by water cooling and holding at 350 ℃,and with the extension of holding time the spinodal wave length is on the increase. With the prolonging of holding time at 350 ℃ before annealing,the fraction of twins increases from 16% to 32% and the percentage of cube texture component declines from 80. 2% to 14. 4%. The cause is attributed to that spinodal structures gradually grow up and restrain the preferential growth of cube oriented grains by forming multiphase structures and twins,at the same time weaken the advantages of preferential nucleation from low temperature recovery. The addition of W inhibits the spinodal decomposition of Ni-32. 7 at% Cu alloy and thus increases the percentage of cube texture component.