| A high quality of large size Zr-based bulk amorphous alloy can be produced by using simple equipment since it is large glass forming ability and wide supercooled liquid region.Meanwhile,it also owns a series of excellent mechanical properties,like high strength,hardness,elastic limit and so on.It is the most promising materials in all the amorphous alloy system which can be applied as the engineering structure materials.However,there are two problems need to be solved before it is widely used in the engineering application.One is the limited glass forming ability.The other is the low room temperature plasticity.This paper aims to improve the glass forming ability and room temperature plasticity of amorphous alloys by finely adjusting the alloy composition and microalloying.In the meantimestudying the effect of fine-tuning and micro-alloying of alloy composition on its comprehensive mechanical properties simultaneously.In this paper,the cylindrical,sheet and plate strip samples are prepared by copper casting.The samples are processed into testing size by using cutting maschine.The structural characteristics of samples are studied by using X-ray diffractometer?XRD?and double spherical aberration transmission electron microscopy?TEM?.The thermal properties is studied by using high temperature differential scanning calorimeter?DSC?analyze thermal parameters,The mechanical property like tensile,compression and three point bending are tested using the universal material testing machine.The elastic modulus is tested by using nano indentation apparatus equipment.The formation mechanism has also been evaluated.Finely adjusting the Cu composition ofamorphous alloy in ZrCuNiAlNb system,the results showed that with the increase of the Cu content,theZrCuNiAlNb amorphous alloy glass forming ability,yield strength,compression strength,compression plasticity and notch toughness firstly increase and then decrease,while the tensile strength and hardness increase in turn.When the content of Cu element is 11.5 at.%,the component amorphous alloy has a critical casting diameter of up to 8 mm.Moreover,its yield strength,compressive strength,compression plasticity and notch toughness reach 2010±25 MPa,2214±20 MPa,8.6±2.1%and 112±1.3 MPa/m1/2;When Cu content is 11.5 at.%,the amorphous alloy has a maximum tensile strength of 1957±11 MPa.The results of amorphous alloy ZrCuNiAlTi system by element Nb microalloying show that with the increase of Nb content,ZrCuNiAlTi?Nb?system of amorphous alloy glass forming ability,yield strength,compression strength,compression plasticity and tensile strength firstly increases and then decrease.The notch toughness value changed a little at the beginning and then fell sharply.Bulk amorphous alloy with critical diameter of 8 mm can be prepared when Nb content is 1.5 at.%.At the same time,it has the maximum yield strength,compressive strength,compressive plastic strength and tensile strength,which can reach 1842±50 MPa,2197±104 MPa,15.8±4.1%and 1744±30 MPa,respectively.The results show that there is no correlation between the tensile strength and the hardness of the two bulk alloys.However,the notch toughness is related to the compression molding of the material.The larger the compression shaping of the material,the higher the notch fracture toughness.Within a certain content range,the fine adjustment of the composition of Cu element or the microalloying of Nb element will cause the matrix alloy chemical composition inhomogeneity,increase the number of nucleation sites in the shear zone,and thus improve the compressive plasticity of the amorphous alloy at room temperature.In contrast,the effect of Nb microalloying on mechanical properties is greater than that of Cu. |
PDF Full Text Request