Volume 18, Issue 4 (July 1990)
Dynamic Loading: A New Microhardness Test Method
A new non-destructive microhardness test method has been developed to measure the microhardness of surface layers, coatings, and homogeneous material using ultra-low loads in the range of (0.025 to 1 N) 2.5 to 100 gf. The method is based on the use of a conventional Vickers indentor that is coupled to a displacement measuring device. An HVL (Vickers Hardness under Load) number is computed from the indentor displacement under load. The test load is applied step-wise up to full nominal test load, yielding a microhardness number at each load increment. Through the use of appropriate computer software, hardness versus load, hardness versus indentation depth, and indentation depth versus load profiles can be generated. The method also provides information regarding creep and elastic recovery properties of the specimen. Because the hardness number is computed from the indentor displacement under load, special operator skills in the optical measurement of the diagonals of the indentation area are not required.