冷风微量润滑纳米粒子体积分数对钛合金磨削性能的影响

采用两步法制备6种不同体积分数的氧化铝纳米流体，对Ti-6Al-4V钛合金进行磨削加工试验。结果表明:磨削区最高温度由氧化铝体积分数为0.5%时的193.6 ℃逐渐降低至1.5%时的最小值183.5 ℃，而当氧化铝体积分数进一步增大时，温度逐渐提升至3.0%时的196.3 ℃；体积分数由0.5%增加至2.5%，比磨削能由74.8 J/mm3下降至最小值64.73 J/mm3；而当体积分数继续增加至3.0%时，比磨削能上升至69.33 J/mm3。黏度随氧化铝纳米粒子的增加而增加，并在体积分数为3.0%时达到235.8 mPa·s。接触角随体积分数的增加先下降，并在体积分数为2.5%时达到最低值45.85°。纳米粒子在基础油中的分散性改变了纳米流体的抗磨减摩与换热性能，进一步影响了磨削性能。 

Effect of nanoparticle volume on grinding performance of titanium alloy in cryogenic air minimum quantity lubrication

A two-step method was used to prepare alumina nanofluids with six different concentrations to perform grinding processing experiments on the titanium alloy Ti-6Al-4V. The results show that the maximum temperature in the grinding zone gradually decreases from 193.6 ℃ when the alumina volume fraction is 0.5% to a minimum value of 183.5 ℃ when it is 1.5%. When the volume fraction is further increased to 3.0%, the maximum temperature is gradually raised to 196.3 ℃. The specific grinding energy decreases from 74.8 J/mm3 to a minimum value of 64.73 J/mm3 while the volume fraction increases from 0.5% to 2.5%. When the volume fraction continues to increase to 3.0%, the specific grinding energy can rise to 69.33 J/mm3. The viscosity increases with the increase of alumina nanoparticles and reaches 235.8 MPa·s when the volume fraction is 3.0%. The contact angle decreases first with the increase of volume fraction and reaches the lowest value of 45.85° when the volume fraction is 2.5%. The dispersion of nanoparticles in the base oil affects the friction reduction and heat transfer performance of the nanofluid and thus the grinding performance.