论文部分内容阅读
用金相分析,X射线衍射相分析和透射电镜观察等手段,全面细致地考察了液相烧结W-Ni-Fe合金的微观组织。发现90％W-Ni-Fe合金中,只要有少量的碳存在,在液相烧结后缓慢冷却的条件下将有析出相产生,经物理化学方法分析鉴定,它是η′类型(A_6B_6C型)碳化物,其结构属于复杂立方晶系(f.c.c.晶格),晶格常数为10.935,其化学组成式可近似写成(Ni,Fe)_6W_6C,其形貌随着冷却速度大小而变化。合金力学性能检验和断口扫描观察的结果证明,此析出相在合金中是脆性相,它严重地降低合金的强度和塑性。通过各种热处理试验,找出了其成因,并制定了避免其产生和将其消除的措施。考虑了快冷与缓冷各自的利弊,为W-Ni-Fe合金的生产提出了一个较合理的制度。
The microstructure of liquid-phase sintered W-Ni-Fe alloy was comprehensively and carefully investigated by means of metallographic analysis, X-ray diffraction and transmission electron microscopy. It was found that 90% W-Ni-Fe alloy, as long as there is a small amount of carbon, after the liquid phase sintering slowly cooled under the conditions of precipitation will have identified by physical and chemical analysis, it is η ’type (A_6B_6C type) Carbide, the structure belongs to the complex cubic system (fcc lattice), the lattice constant of 10.935, the chemical composition formula can be written as (Ni, Fe) _6W_6C, the morphology changes with the size of the cooling rate. The mechanical properties of the alloy and the results of the fracture scanning observation show that the precipitated phase is a brittle phase in the alloy, which seriously reduces the strength and ductility of the alloy. Through a variety of heat treatment tests to identify its causes, and developed to avoid the production and elimination of measures. Considering the pros and cons of rapid cooling and slow cooling respectively, a more reasonable system is proposed for the production of W-Ni-Fe alloy.