Ti66Nb18Cu6.4Ni6.1Al3.5細(xì)晶復(fù)合材料
(1. 華南理工大學(xué) 國家金屬材料近凈成形工程技術(shù)研究中心，廣州 510640；
2. 內(nèi)蒙古第一機(jī)械制造(集團(tuán))有限公司 車輛工程研究院，包頭 014030)
摘 要: 基于改進(jìn)的非晶形成合金體系，選取Ti66Nb18Cu6.4Ni6.1Al3.5合金為研究對象，通過放電等離子燒結(jié)機(jī)械合金化制備的非晶合金粉末，結(jié)合非晶晶化法，合成以高Nb含量的晶化β-Ti(Nb)延性相為基體的塊狀細(xì)晶復(fù)合材料。利用X射線衍射(XRD)、差示掃描量熱儀(DSC)、掃描電子顯微鏡(SEM)、透射電子顯微鏡(TEM)和萬能材料試驗機(jī)等手段對合成的非晶合金粉末和細(xì)晶復(fù)合材料進(jìn)行表征分析。結(jié)果表明：球磨60 h后，初始混合粉末絕大部分轉(zhuǎn)變成了非晶相，其玻璃轉(zhuǎn)變溫度、晶化溫度、晶化峰值溫度和熔化溫度分別為750 K、830 K、847 K和1422 K，表明Nb含量的增加顯著提高合金體系的熱穩(wěn)定性。另外，合成的塊狀鈦基細(xì)晶復(fù)合材料的顯微結(jié)構(gòu)為β-Ti延性相包圍(Cu, Ni)-Ti2相，其相區(qū)尺寸均大于1 μm。當(dāng)升溫速率為167 K/min、燒結(jié)溫度為1 373 K時，合成的復(fù)合材料密度、屈服強(qiáng)度、斷裂強(qiáng)度和斷裂應(yīng)變分別為5.64 g/cm3、1 705.8 MPa、2 126.4 MPa和5.4%。
關(guān)鍵字: 非晶復(fù)合材料；機(jī)械合金化；放電等離子燒結(jié)；晶化
（1. National Engineering Research Center of Near-net-shape Forming for Metallic Materials,
South China University of Technology, Guangzhou 510640, China;
2. Automobile Engineering Academy, Inner Mongolia First Machinery Group Corporation, Baotou 014030, China）
Abstract:Ti66Nb18Cu6.4Ni6.1Al3.5 alloy system was selected as the study object based on modified amorphous alloy system. The bulk Ti66Nb18Cu6.4Ni6.1Al3.5 fine grained composites with matrix of crystallized β-Ti(Nb) ductile phase were fabricated by spark plasma sintering of mechanical alloyed amorphous alloy powders coupled with the method of crystallization of amorphous phase. X-ray diffractometer (XRD), differential scanning calorimeter (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and universal materials tester were employed to investigate the alloyed amorphous powders and the fabricated composites. The results show that the initial mixed powders are predominately alloyed into amorphous structure after milling for 60 h. The crystallization temperature (Tx), crystallization peak temperature (Tp) and melting point (Tm) of the alloyed amorphous powders are 750 K, 830 K, 847 K and 1 422 K, respectively. This indicates that the increased Nb content enhances significantly the thermal stability of alloyed powders. In addition, the fabricated composites has a microstructure of (Cu, Ni)-Ti2 phase surrounded by ductile β-Ti phase. The scale of the two phase regions is above 1 μm. Under a heating rate of 167 K/min and a sintering temperature of 1 373 K, the fabricated composite has a density of 5.64 g/cm3, a yield stress of 1 705.8 MPa, a fracture stress of 2 126.4 MPa and a fracture strain of 5.4%.
Key words: amorphous alloy composite; mechanical alloying; spark plasma sintering; crystallization
