等通道擠壓制備醫(yī)用超細(xì)晶Mg-3Sn-0.5Mn合金及其力學(xué)性能

等通道擠壓制備醫(yī)用超細(xì)晶Mg-3Sn-0.5Mn合金及其力學(xué)性能Mechanical Properties of Biomedical Ultrafine Grained Mg-3Sn-0.5Mn Alloy Processed by Equal-channel Angular Pressing

采用等通道轉(zhuǎn)角擠壓(equal channel angular pressing，ECAP)方法成功擠壓了Mg-3Sn-0.5Mn合金，采用OM和TEM觀察了ECAP過(guò)程中微觀組織和晶粒尺寸的變化，測(cè)試了ECAP后Mg-3Sn-0.5Mn合金的力學(xué)性能與腐蝕性能，通過(guò)XRD觀察了ECAP變形后的織構(gòu)取向變化。結(jié)果顯示，ECAP后得到了超細(xì)晶Mg-3Sn-0.5Mn合金組織，在320 ℃下經(jīng)過(guò)4道次擠壓后平均晶粒尺寸細(xì)化到了1.65 μm，TEM觀察局部晶粒細(xì)化到了0.8 μm，晶粒細(xì)化是劇烈塑性變形與再結(jié)晶共同作用的結(jié)果。4道次變形后，延伸率從22.2% 上升到58.6%。，抗拉強(qiáng)度從242.8MPa下降到195.6MPa ，延伸率提高了約3倍，強(qiáng)度有略微的下降。ECAP后的Mg-3Sn-0.5Mn合金織構(gòu)優(yōu)勢(shì)取向發(fā)生了顯著改變，這種變化有利于滑移系的開(kāi)動(dòng)，提高了材料的塑性，但對(duì)強(qiáng)度有一定的不利影響。ECAP后的Mg-3Sn-0.5Mn合金力學(xué)性能受到改變的織構(gòu)優(yōu)勢(shì)取向和細(xì)晶強(qiáng)化的共同影響。

Mg alloy has attracted researchers’ attention as applied for novel biomedical material because its super corrosion property and well biocompatibility. Ultra-fine grain (UFG) Mg alloy has certain advantages in the development of medical devices because of its good plasticity and corrosion resistance. Equal channel angular pressing (ECAP) was performed on Mg-3Sn-0.5Mn alloy successfully. The microstructure and grain size were observed and measured by OM and TEM. The mechanical property was tested by microhardness and tensile test, the texture oriented was experimented by XRD, and the corrosion property was tested by electrochemical experiment. After 4 passes in the temperature 320℃, the average grain size of Mg-3Sn-0.5Mn alloy reached 1.65 μm, and local grain size reached 0.8 μm according to TEM results. The grain refinement was caused by severe plastic deformation and recrystallization. The elongation increased from 22.2% to 58.9%, the tensile strength decreased from 242.8MPa to 195.6MPa after 4 passes deformation. The mechanical tests showed an improvement in the elongation after 4 passes, which were about 3 times higher than in the as-extruded sample, whereas the tensile strength decreased slightly. The texture of Mg-3Sn-0.5Mn alloy changed obviously which contributed to the actuating of the slip system. This change of texture contributed to the improvement of fracture elongation and decrease of tensile strength. The mechanical property of Mg-3Sn-0.5Mn alloy after ECAP was affected by the texture orientation and grain strengthening.

全文下載：https://pan.baidu.com/s/1i5IKAzj