【摘要】 采用光学显微镜、扫描电镜、线膨胀系数测试、弹性模量测试、显微硬度测试等方法,研究了4J36合金的成分添加及退火温度对显微组织、线膨胀系数、弹性模量、强度、硬度及塑性等性能的影响。结果表明,试验合金中添加C、Si、Mn总量的增加,有利于提高合金的弹性模量、强度及硬度,但会导致线膨胀系数线性增加。三炉次合金中,C、Si、Mn总量最高的4J36合金能很好地满足工况环境下性能指标要求。随退火温度的升高,奥氏体晶粒逐渐长大,并伴有少量的退火孪晶,合金的塑韧性较锻态显著提高,拉伸断口呈韧性断裂特征。退火处理前的锻态合金组织为单一的奥氏体,但组织均匀性较差。在820~850℃范围内进行退火处理后,合金晶粒组织均匀,综合力学性能优于其他温度下处理的合金。更多还原

【Abstract】 Microstructure,coefficient of thermal expansion,modulus of elasticity,strength,hardness and ductility of 4J36 alloy were investigated by means of optical microscopy,scanning electron microscopy,coefficient of thermal expansion test,modulus of elasticity test and hardness measurement.The results indicate that the increasing of the total contents of C,Si and Mn is in favor of the improvements of modulus of elasticity,strength and hardness,but resulting in the linear increase of coefficient of thermal expansion.Among the three furnaces,No.3 4J36 alloy,with the highest total content of C、Si and Mn,can meet the requirement of performance specification under operating condition very well.With the annealing temperature increasing,the austenite grains grow up gradually accompanied by a small amount of annealing twin crystals.Meanwhile,the plasticity and toughness of the alloy are significantly improved compared with that in forged state,and the tensile fracture is characterized by ductile rupture.The microstructure of the forged alloy before annealing is characterized by single-phase of austenite,but is less uniformity.When annealing at 820-850 ℃,the grain size of the alloy becomes more uniform,and the comprehensive properties are better than those of treated at the other annealing temperatures.更多还原