Journal of Materials Science
The thermal stability and formation range of amorphous Al(100-x)Ln(5)Ni(x) (x = 3, 5, 9, 13, 17, 21, 23) alloys were studied by differential scanning calorimetry and X-ray diffraction techniques. The microhardness, H-v, of these Al-RE-Ni alloys was measured. The experimental results show that toughness was adversely affected by increase in the nickel content. The atomic size factor was applied to explain the formation mechanism of aluminium-based amorphous alloys by the atomic clusters model. The minimum concentration of nickel in Al-RE-Ni alloys results from the effective atomic volume difference of the nickel and aluminium atoms.
关键词:
metallic glasses
Journal of Non-Crystalline Solids
Dynamic fracture characteristics have been observed and interpreted for FeMoSiB amorphous alloy ribbons. Crack branching and stress wave induced cracking is the main features of dynamic fracture. Branching of the main crack occurs at the critical stress intensity K-IB at the crack tip. Plane strain fracture toughness K-Ic and K-IB is determined to be 11 and 35 MPa m(0.5), respectively. It is deduced that crack branching is the necessary condition for generation of a compressive longitudinal wave for FeMoSiB amorphous ribbons. Stress wave induced cracking occurs when the amplitude of the reflected compressive longitudinal wave reaches the tensile strength. The amplitude of the stress wave is estimated to be at least 1.1 GPa to induce cracks at the originating laser hole. The reason why the dynamic characteristics of amorphous alloy have not been observed before may be attributed to the small dimension and shape of past specimens. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
metallic glasses
王美玲
,
惠希东
,
冯强
,
陈国良
稀有金属材料与工程
采用真空铜模吸铸和单辊真空薄带技术制备出直径5 mm的Zr47Ti12.9Cu1 1Ni9.6Be16.7Nb2.8金属玻璃棒材和相同成分厚30 μm的金属玻璃薄带.利用热分析技术和Kissinger方法分析计算了不同尺寸金属玻璃的热稳定性参数,主要包括:玻璃转变温度Tg,晶化温度Tx,玻璃转变和晶化激活能Eg、Ex等.结果表明:Zr47Ti12.9Cu11Ni9.6Be16.7Nb2.8金属玻璃在热稳定性上表现出“越小越稳定”的特征,薄带的热稳定性参数均高于棒材,表现出更好的热稳定性.不同尺寸Zr47Ti12.9Cu11Ni9.6Be 16.7Nb2.8金属玻璃的晶化行为进一步验证了这一特征:在晶化温度远低于金属玻璃薄带情况下,棒材却更易晶化,晶化过程中获得了比金属玻璃薄带更加完整的晶化组织.
关键词:
Zr47Ti12.9Cu11Ni9.6Be16.7Nb2.8
,
金属玻璃
,
热稳定性
,
尺寸效应
党一纵
,
宫声凯
,
薛云飞
,
王鲁
中国有色金属学报
利用铜模铸造法制备Zr50Cu50二元非晶合金,并研究铜模温度、保护气体对Zr50Cu50合金非晶形成的影响.熔液的冷却速率是由铜模温度以及保护气性质共同决定的,相比于氩、氦作为保护性气体不但有效提高熔液的冷却速率,而且在超低温制备环境下仍能保持样品表面光滑.在此研究基础上,利用氦作为保护气,在液氮作为铜模冷却介质的超低温环境下(79 K),制备出表面光滑、直径为2.5 mm的Zr50Cu50大块非晶合金,该尺寸超越了之前所报道的Zr50Cu50非晶合金的最大尺寸(2 mm).
关键词:
非晶合金
,
模具温度
,
保护气体
,
冷却速度
,
非晶形成能力
