摘要
Abstract
Objectives:With the development of the modern manufacturing industry,the requirements for material ma-chining accuracy and surface quality are increases continuously.For the precision grinding of high hardness and high wear-resistant materials,superhard material grinding wheels are required to possess high processing efficiency and dur-ability.Intermetallic compound bond diamond grinding wheels have the wear resistance of metal grinding wheels and the self-sharpness of ceramic grinding wheels simultaneously,but they still lacks of sharpness or shape retention when machining hard and brittle materials at high loads and high speeds.To improve the sharpness and shape retention of Cu3Sn intermetallic compound diamond grinding wheels,this study investigates the addition of TiH2.Cu3Sn ball-milling powders,diamond grinding blocks,and grinding wheels with different TiH2 additions are prepared.Methods:The ef-fects of TiH2 addition on the grinding performance of Cu3Sn intermetallic diamond grinding wheels are investigated us-ing testing and analyzing the micro-morphology,oxygen content,physical phase composition,thermal effect,and mech-anical properties.Results:(1)TiH2 was added to the Cu3Sn intermetallic compound bond,and the mixture is ball milled together.TiH2 inhibits the increase in oxygen content,which improves the properties of the ball-milled bond powder and facilitated the sintering process.When TiH2 is added with a mass fraction of 2.0%,the oxygen content is reduced from 0.67%to a minimum value of 0.51%.(2)TiH2 decomposes into Ti and H2 during the sintering process,and Ti could re-act with the C atoms on the surface of the diamond to form a Ti-C bond.This chemical bonding between the metal bond and diamonds could increased the bonding strength.TiH2 could improve the mechanical properties of diamond grinding blocks,but a larger amount of TiH2 increased the pores in the metal bond,which reduced its strength.When TiH2 mass fraction is 1.5%,the flexural strength reaches the maximum value of 80.74 MPa,and the addition of 2.0%TiH2 increased the Rockwell hardness to reaches a maximum value of 109.88 HRB.(3)Adding of an appropriate amount of TiH2 forms a chemical metallurgical bond between diamonds and the bonding agent,which strengthens the holding force of the bonding agent to the diamonds,increases the protrusion height and chip space on the working sur-face,and improves the sharpness of the grinding wheel.At the same time,it can avoid the premature shedding of dia-monds,reducing the consumption of the working layer and improving the shape retention of the grinding wheel.The grinding wheels prepared by adding a certain amount of TiH2 prior to the ball milling treatment of Cu3Sn bond powder exhibited better grinding performance.Both sharpness and shape retention are enhanced.When grinding YG8 cemented carbide,the addition of 2.0%TiH2 enhanced the fastest feed rate of the grinding wheel from 0.020 mm/feed to 0.035 mm/feed.Meanwhile,the grinding ratio of the wheel reached a maximum value of 172.03,which is enhanced by 237%compared with the specimen without TiH2 addition.Conclusions:In this paper,TiH2 is added to Cu3Sn inter-metallic compounds by ball milling,and the oxygen content of the bond powder is reduced.At the same time,the carbide-formation element Ti reacts with the diamond to form a chemical metallurgical bond,which improves the bond-ing strength between the diamond and the bonding agent.This results in improved grinding performance of the diamond wheel and provides a reference for the design and development of diamond grinding wheels with high sharpness and high conformal retention.关键词
TiH2/金属间化合物/力学性能/磨削比Key words
TiH2/intermetallic compounds/mechanical properties/grinding ratio分类
金属材料
