Effect Of C,Nb And Zr Elements On Tribological Properties Of Ni₃Al-Ni₃V Alloy

With the rapid development of the aerospace field,the requirements for high-temperature bearing materials used in the field have also been further improved,and high-temperature bearings are prone to wear and failure during service.Therefore,the material research and development of aero-engine bearings will be a new research area.Although the Ni₃Al-Ni₃V alloy has good mechanical properties and high temperature self-lubricating properties,the wear performance of the Ni₃Al-Ni₃V alloy at room temperature is still slightly insufficient.In view of the normal temperature wear in the initial stage of the high temperature bearing,Ni₃Al-Ni₃V is selected in this paper.Ni₃Al-Ni₃V（C-Nb）alloy and Ni₃Al-Ni₃V（Zr）alloy as research objects to study the wear characteristics of the two alloys.In addition,this paper proposes a ball-block sliding wear simulation method based on the combination of Abaqus and subroutines Umeshmotion;compares the ball-block sliding wear simulation results with the wear test results to verify the accuracy of the wear coefficient of Ni₃Al-Ni₃V alloys The performance and reliability of the method make up for the deficiency of the previous research method of alloy wear coefficient and Ni₃Al-Ni₃V（Zr）alloy wear parameters.The main findings are as follows:（1）The microstructure of Ni₃Al-Ni₃V alloy is composed of bulk primary Ni₃Al precipitation and Ni₃Al+Ni₃V phase;Ni₃Al-Ni₃V（C-Nb）alloy is mainly composed of bulk primary Ni₃Al precipitation,Ni₃Al+Ni₃V phase and carbides at grain boundaries;The hardness and wear properties of the three Ni₃Al-Ni₃V（C-Nb）alloys are better than those of Ni₃Al-Ni₃V alloy,and the sample1 Ni₃Al-Ni₃V（C-Nb）alloy is the best.The Gibbs free energies of Al and V in Ni₃Al-Ni₃V alloy and three Ni₃Al-Ni₃V（C-Nb）alloys are all less than-120 KJ/mol,and it is easy to react with water molecules in the air to generate H atoms during wear.When the atomic percentage of Al is When it is greater than 5.53 at.%,environmental brittleness is likely to occur.（2）The microstructure of Ni₃Al-Ni₃V（Zr）alloy is mainly composed of bulk primary Ni₃Al precipitation phase,Ni₃Al+Ni₃V phase,Zr-rich phase and Ni₅Zr phase at grain boundary 1～4μm or 250～500 nm Ni₃Al-Ni₃V（Zr）alloy.The friction and wear performance of Ni₃Al-Ni₃V（Zr）alloy is better than that of Ni₃Al-Ni₃V alloy;with the increase of P·V value,the friction coefficient of Ni₃Al-Ni₃V（Zr）alloy tends to decrease,and the wear first decreases and then increases.Among them,When the P·V value is 1 N·（m/s）,the wear rate is the lowest.Zr element improves the wear environment of Ni₃Al-Ni₃V alloy The brittleness is due to the depletion of Al at the Ni₃Al phase boundary on the freshly worn surface during the wear process,which reduces or eliminates the contact between the active element Al and the water vapor in the atmospheric environment,and inhibits the atomic state of H.In the nanoscale Ni₃Al-Ni₃V（Zr）alloy,the high volume fraction of Ni₃Al phase boundary makes the alloy have better wear resistance.（3）Based on the ball-block sliding wear simulation method combined with Abaqus and subroutines,The ball-block sliding wear simulation model corrected by this method is:h=2.4092941×10^-7〔πant（3/E）^1/2〕p^3/2/H,The wear coefficient k of Ni3Al-Ni3V（Zr）alloy is1.20464705E-07,and the relative error between ball-block sliding wear simulation and experiment is within 10%,which indicates that the method is accurate and reliable.